DefaultOptions implemented as module factory

package.json

@@ -40,7 +40,7 @@
         "test:all": "NODE_PATH=src node node_modules/.bin/ava",
         "lint": "tslint -p tsconfig.json",
         "validate:tslint": "tslint-config-prettier-check ./tslint.json",
-        "prepublishOnly": "yarn lint && yarn test && yarn tsc"
+        "prepublishOnly": "yarn lint && yarn test && yarn tsc -d"
     },
     "dependencies": {},
     "devDependencies": {

src/functions/accumulator.ts

@@ -1,5 +1,4 @@
 import { Transform, TransformOptions } from "stream";
-import { batch } from ".";
 
 export enum FlushStrategy {
     rolling = "rolling",
@@ -129,24 +128,24 @@ export function accumulator(
     keyBy?: string,
     options?: TransformOptions,
 ): Transform {
-    if (flushStrategy === FlushStrategy.sliding) {
+    switch (flushStrategy) {
-        return sliding(batchSize, keyBy, options);
+        case FlushStrategy.sliding:
-    } else if (flushStrategy === FlushStrategy.rolling) {
+            return sliding(batchSize, keyBy, options);
-        return rolling(batchSize, keyBy, options);
+        case FlushStrategy.rolling:
-    } else {
+            return rolling(batchSize, keyBy, options);
-        return batch(batchSize);
     }
 }
 
 export function accumulatorBy<T, S extends FlushStrategy>(
-    flushStrategy: S,
+    flushStrategy: FlushStrategy,
     iteratee: AccumulatorByIteratee<T>,
     options?: TransformOptions,
 ): Transform {
-    if (flushStrategy === FlushStrategy.sliding) {
+    switch (flushStrategy) {
-        return slidingBy(iteratee, options);
+        case FlushStrategy.sliding:
-    } else {
+            return slidingBy(iteratee, options);
-        return rollingBy(iteratee, options);
+        case FlushStrategy.rolling:
+            return rollingBy(iteratee, options);
     }
 }
 

src/functions/baseFunctions.ts

@@ -1,23 +0,0 @@
-export { accumulator, accumulatorBy } from "./accumulator";
-export { batch } from "./batch";
-export { child } from "./child";
-export { collect } from "./collect";
-export { concat } from "./concat";
-export { duplex } from "./duplex";
-export { filter } from "./filter";
-export { flatMap } from "./flatMap";
-export { fromArray } from "./fromArray";
-export { join } from "./join";
-export { last } from "./last";
-export { map } from "./map";
-export { merge } from "./merge";
-export { parallelMap } from "./parallelMap";
-export { parse } from "./parse";
-export { rate } from "./rate";
-export { reduce } from "./reduce";
-export { replace } from "./replace";
-export { split } from "./split";
-export { stringify } from "./stringify";
-export { unbatch } from "./unbatch";
-export { compose } from "./compose";
-export { demux } from "./demux";

src/functions/batch.ts

@@ -3,9 +3,7 @@ import { Transform, TransformOptions } from "stream";
 export function batch(
     batchSize: number = 1000,
     maxBatchAge: number = 500,
-    options: TransformOptions = {
+    options: TransformOptions = {},
-        objectMode: true,
-    },
 ): Transform {
     let buffer: any[] = [];
     let timer: NodeJS.Timer | null = null;

src/functions/child.ts

@@ -1,5 +1,5 @@
 import { ChildProcess } from "child_process";
-import { duplex } from "./baseFunctions";
+import { duplex } from "./duplex";
 
 export function child(childProcess: ChildProcess) {
     if (childProcess.stdin === null) {

src/functions/demux.ts

@@ -25,7 +25,7 @@ const eventsTarget = {
 type DemuxStreams = NodeJS.WritableStream | NodeJS.ReadWriteStream;
 
 export function demux(
-    construct: () => DemuxStreams,
+    construct: (destKey?: string) => DemuxStreams,
     demuxBy: string | ((chunk: any) => string),
     options?: WritableOptions,
 ): Writable {

src/functions/flatMap.ts

@@ -4,9 +4,7 @@ export function flatMap<T, R>(
     mapper:
         | ((chunk: T, encoding: string) => R[])
         | ((chunk: T, encoding: string) => Promise<R[]>),
-    options: TransformOptions = {
+    options?: TransformOptions,
-        objectMode: true,
-    },
 ): Transform {
     return new Transform({
         ...options,

src/functions/index.ts

@@ -1,214 +1,262 @@
-import { Transform } from "stream";
+import {
-import * as baseFunctions from "./baseFunctions";
+    Transform,
+    TransformOptions,
+    WritableOptions,
+    ReadableOptions,
+} from "stream";
+import { accumulator, accumulatorBy } from "./accumulator";
+import { batch } from "./batch";
+import { child } from "./child";
+import { collect } from "./collect";
+import { concat } from "./concat";
+import { duplex } from "./duplex";
+import { filter } from "./filter";
+import { flatMap } from "./flatMap";
+import { fromArray } from "./fromArray";
+import { join } from "./join";
+import { last } from "./last";
+import { map } from "./map";
+import { merge } from "./merge";
+import { parallelMap } from "./parallelMap";
+import { parse } from "./parse";
+import { rate } from "./rate";
+import { reduce } from "./reduce";
+import { replace } from "./replace";
+import { split } from "./split";
+import { stringify } from "./stringify";
+import { unbatch } from "./unbatch";
+import { compose } from "./compose";
+import { demux } from "./demux";
 
-/**
+export default function mhysa(defaultOptions?: TransformOptions) {
- * Convert an array into a Readable stream of its elements
+    function withDefaultOptions<T extends any[], R>(
- * @param array Array of elements to stream
+        n: number,
- */
+        fn: (...args: T) => R,
-export const fromArray = baseFunctions.fromArray;
+    ): (...args: T) => R {
+        return (...args) => {
+            const options = {
+                ...defaultOptions,
+                ...((args[n] || {}) as TransformOptions | {}),
+            };
+            const provided = args.slice(0, n);
+            const nextArgs = [
+                ...provided,
+                ...Array(n - provided.length).fill(undefined),
+                options,
+            ] as T;
+            return fn(...nextArgs) as R;
+        };
+    }
 
-/**
+    return {
- * Return a ReadWrite stream that maps streamed chunks
+        /**
- * @param mapper Mapper function, mapping each (chunk, encoding) to a new chunk (or a promise of such)
+         * Convert an array into a Readable stream of its elements
- * @param options?
+         * @param array Array of elements to stream
- * @param options.readableObjectMode? Whether this stream should behave as a readable stream of objects
+         */
- * @param options.writableObjectMode? Whether this stream should behave as a writable stream of objects
+        fromArray,
- */
-export const map = baseFunctions.map;
 
-/**
+        /**
- * Return a ReadWrite stream that flat maps streamed chunks
+         * Return a ReadWrite stream that maps streamed chunks
- * @param mapper Mapper function, mapping each (chunk, encoding) to an array of new chunks (or a promise of such)
+         * @param mapper Mapper function, mapping each (chunk, encoding) to a new chunk (or a promise of such)
- * @param options?
+         * @param options?
- * @param options.readableObjectMode? Whether this stream should behave as a readable stream of objects
+         * @param options.readableObjectMode? Whether this stream should behave as a readable stream of objects
- * @param options.writableObjectMode? Whether this stream should behave as a writable stream of objects
+         * @param options.writableObjectMode? Whether this stream should behave as a writable stream of objects
- */
+         */
-export const flatMap = baseFunctions.flatMap;
+        map: withDefaultOptions(1, map),
 
-/**
+        /**
- * Return a ReadWrite stream that filters out streamed chunks for which the predicate does not hold
+         * Return a ReadWrite stream that flat maps streamed chunks
- * @param predicate Predicate with which to filter scream chunks
+         * @param mapper Mapper function, mapping each (chunk, encoding) to an array of new chunks (or a promise of such)
- * @param options?
+         * @param options?
- * @param options.objectMode? Whether this stream should behave as a stream of objects.
+         * @param options.readableObjectMode? Whether this stream should behave as a readable stream of objects
- */
+         * @param options.writableObjectMode? Whether this stream should behave as a writable stream of objects
-export const filter = baseFunctions.filter;
+         */
+        flatMap: withDefaultOptions(1, flatMap),
 
-/**
+        /**
- * Return a ReadWrite stream that reduces streamed chunks down to a single value and yield that
+         * Return a ReadWrite stream that filters out streamed chunks for which the predicate does not hold
- * value
+         * @param predicate Predicate with which to filter scream chunks
- * @param iteratee Reducer function to apply on each streamed chunk
+         * @param options?
- * @param initialValue Initial value
+         * @param options.objectMode? Whether this stream should behave as a stream of objects.
- * @param options?
+         */
- * @param options.readableObjectMode? Whether this stream should behave as a readable stream of objects
+        filter: withDefaultOptions(1, filter),
- * @param options.writableObjectMode? Whether this stream should behave as a writable stream of objects
- */
-export const reduce = baseFunctions.reduce;
 
-/**
+        /**
- * Return a ReadWrite stream that splits streamed chunks using the given separator
+         * Return a ReadWrite stream that reduces streamed chunks down to a single value and yield that
- * @param separator? Separator to split by, defaulting to "\n"
+         * value
- * @param options? Defaults to encoding: utf8
+         * @param iteratee Reducer function to apply on each streamed chunk
- * @param options.encoding? Encoding written chunks are assumed to use
+         * @param initialValue Initial value
- */
+         * @param options?
-export const split = baseFunctions.split;
+         * @param options.readableObjectMode? Whether this stream should behave as a readable stream of objects
+         * @param options.writableObjectMode? Whether this stream should behave as a writable stream of objects
+         */
+        reduce: withDefaultOptions(2, reduce),
 
-/**
+        /**
- * Return a ReadWrite stream that joins streamed chunks using the given separator
+         * Return a ReadWrite stream that splits streamed chunks using the given separator
- * @param separator Separator to join with
+         * @param separator? Separator to split by, defaulting to "\n"
- * @param options? Defaults to encoding: utf8
+         * @param options? Defaults to encoding: utf8
- * @param options.encoding? Encoding written chunks are assumed to use
+         * @param options.encoding? Encoding written chunks are assumed to use
- */
+         */
-export const join = baseFunctions.join;
+        split,
 
-/**
+        /**
- * Return a ReadWrite stream that replaces occurrences of the given string or regular expression  in
+         * Return a ReadWrite stream that joins streamed chunks using the given separator
- * the streamed chunks with the specified replacement string
+         * @param separator Separator to join with
- * @param searchValue Search string to use
+         * @param options? Defaults to encoding: utf8
- * @param replaceValue Replacement string to use
+         * @param options.encoding? Encoding written chunks are assumed to use
- * @param options? Defaults to encoding: utf8
+         */
- * @param options.encoding Encoding written chunks are assumed to use
+        join: withDefaultOptions(1, join),
- */
-export const replace = baseFunctions.replace;
 
-/**
+        /**
- * Return a ReadWrite stream that parses the streamed chunks as JSON. Each streamed chunk
+         * Return a ReadWrite stream that replaces occurrences of the given string or regular expression  in
- * must be a fully defined JSON string in utf8.
+         * the streamed chunks with the specified replacement string
- */
+         * @param searchValue Search string to use
-export const parse = baseFunctions.parse;
+         * @param replaceValue Replacement string to use
+         * @param options? Defaults to encoding: utf8
+         * @param options.encoding Encoding written chunks are assumed to use
+         */
+        replace,
 
-/**
+        /**
- * Return a ReadWrite stream that stringifies the streamed chunks to JSON
+         * Return a ReadWrite stream that parses the streamed chunks as JSON. Each streamed chunk
- * @param options?
+         * must be a fully defined JSON string in utf8.
- * @param options.pretty If true, whitespace is inserted into the stringified chunks.
+         */
- *
+        parse,
- */
-export const stringify = baseFunctions.stringify;
 
-/**
+        /**
- * Return a ReadWrite stream that collects streamed chunks into an array or buffer
+         * Return a ReadWrite stream that stringifies the streamed chunks to JSON
- * @param options?
+         * @param options?
- * @param options.objectMode? Whether this stream should behave as a stream of objects
+         * @param options.pretty If true, whitespace is inserted into the stringified chunks.
- */
+         *
-export const collect = baseFunctions.collect;
+         */
+        stringify,
 
-/**
+        /**
- * Return a Readable stream of readable streams concatenated together
+         * Return a ReadWrite stream that collects streamed chunks into an array or buffer
- * @param streams Readable streams to concatenate
+         * @param options?
- */
+         * @param options.objectMode? Whether this stream should behave as a stream of objects
-export const concat = baseFunctions.concat;
+         */
+        collect: withDefaultOptions(0, collect),
 
-/**
+        /**
- * Return a Readable stream of readable streams concatenated together
+         * Return a Readable stream of readable streams concatenated together
- * @param streams Readable streams to merge
+         * @param streams Readable streams to concatenate
- */
+         */
-export const merge = baseFunctions.merge;
+        concat,
 
-/**
+        /**
- * Return a Duplex stream from a writable stream that is assumed to somehow, when written to,
+         * Return a Readable stream of readable streams concatenated together
- * cause the given readable stream to yield chunks
+         * @param streams Readable streams to merge
- * @param writable Writable stream assumed to cause the readable stream to yield chunks when written to
+         */
- * @param readable Readable stream assumed to yield chunks when the writable stream is written to
+        merge,
- */
-export const duplex = baseFunctions.duplex;
 
-/**
+        /**
- * Return a Duplex stream from a child process' stdin and stdout
+         * Return a Duplex stream from a writable stream that is assumed to somehow, when written to,
- * @param childProcess Child process from which to create duplex stream
+         * cause the given readable stream to yield chunks
- */
+         * @param writable Writable stream assumed to cause the readable stream to yield chunks when written to
-export const child = baseFunctions.child;
+         * @param readable Readable stream assumed to yield chunks when the writable stream is written to
+         */
+        duplex,
 
-/**
+        /**
- * Return a Promise resolving to the last streamed chunk of the given readable stream, after it has
+         * Return a Duplex stream from a child process' stdin and stdout
- * ended
+         * @param childProcess Child process from which to create duplex stream
- * @param readable Readable stream to wait on
+         */
- */
+        child,
-export const last = baseFunctions.last;
 
-/**
+        /**
- * Stores chunks of data internally in array and batches when batchSize is reached.
+         * Return a Promise resolving to the last streamed chunk of the given readable stream, after it has
- * @param batchSize Size of the batches, defaults to 1000.
+         * ended
- * @param maxBatchAge? Max lifetime of a batch, defaults to 500
+         * @param readable Readable stream to wait on
- */
+         */
-export function batch(batchSize?: number, maxBatchAge?: number): Transform {
+        last,
-    return baseFunctions.batch(batchSize, maxBatchAge);
+
+        /**
+         * Stores chunks of data internally in array and batches when batchSize is reached.
+         * @param batchSize Size of the batches, defaults to 1000.
+         * @param maxBatchAge? Max lifetime of a batch, defaults to 500
+         * @param options?
+         * @param options.objectMode? Whether this stream should behave as a stream of objects
+         */
+        batch: withDefaultOptions(2, batch),
+
+        /**
+         * Unbatches and sends individual chunks of data.
+         * @param options?
+         * @param options.objectMode? Whether this stream should behave as a stream of objects
+         */
+        unbatch: withDefaultOptions(0, unbatch),
+
+        /**
+         * Limits rate of data transferred into stream.
+         * @param targetRate? Desired rate in ms.
+         * @param period? Period to sleep for when rate is above or equal to targetRate.
+         * @param options?
+         */
+        rate: withDefaultOptions(2, rate),
+
+        /**
+         * Limits number of parallel processes in flight.
+         * @param parallel Max number of parallel processes.
+         * @param func Function to execute on each data chunk.
+         * @param pause Amount of time to pause processing when max number of parallel processes are executing.
+         */
+        parallelMap: withDefaultOptions(3, parallelMap),
+
+        /**
+         * Accummulates and sends batches of data. Each chunk that flows into the stream is checked against items
+         * in the buffer. How the buffer is mutated is based on 1 of 2 possible buffering strategies:
+         * 	1. Sliding
+         * 		- If the buffer is larger than the batchSize, the front of the buffer is popped to maintain
+         * 		the batchSize. When no key is provided, the batchSize is effectively the buffer length. When
+         * 		a key is provided, the batchSize is based on the value at that key. For example, given a key
+         * 		of `timestamp` and a batchSize of 3000, each item in the buffer will be guaranteed to be
+         * 		within 3000 timestamp units from the first element. This means that with a key, multiple elements
+         * 		may be spliced off the front of the buffer. The buffer is then pushed into the stream.
+         * 	2. Rolling
+         * 		- If the buffer is larger than the batchSize, the buffer is cleared and pushed into the stream.
+         * 		When no key is provided, the batchSize is the buffer length. When a key is provided, the batchSize
+         * 		is based on the value at that key. For example, given a key of `timestamp` and a batchSize of 3000,
+         * 		each item in the buffer will be guaranteed to be within 3000 timestamp units from the first element.
+         * @param flushStrategy Buffering strategy to use.
+         * @param batchSize Size of the batch (in units of buffer length or value at key).
+         * @param keyBy Key to determine if element fits into buffer or items need to be cleared from buffer.
+         * @param options Transform stream options
+         */
+        accumulator: withDefaultOptions(3, accumulator),
+
+        /**
+         * Accummulates and sends batches of data. Each chunk that flows into the stream is checked against items
+         * in the buffer. How the buffer is mutated is based on 1 of 2 possible buffering strategies:
+         * 	1. Sliding
+         * 		- If the iteratee returns false, the front of the buffer is popped until iteratee returns true. The
+         * 		item is pushed into the buffer and buffer is pushed into stream.
+         * 	2. Rolling
+         * 		- If the iteratee returns false, the buffer is cleared and pushed into stream. The item is
+         * 		then pushed into the buffer.
+         * @param flushStrategy Buffering strategy to use.
+         * @param iteratee Function applied to buffer when a chunk of data enters stream to determine if element fits into
+         * or items need to be cleared from buffer.
+         * @param options Transform stream options
+         */
+        accumulatorBy: withDefaultOptions(2, accumulatorBy),
+
+        /**
+         * Composes multiple streams together. Writing occurs on first stream, piping occurs from last stream.
+         * @param streams Array of streams to compose. Minimum of two.
+         * @param options Transform stream options
+         */
+        compose: withDefaultOptions(1, compose),
+
+        /**
+         * Composes multiple streams together. Writing occurs on first stream, piping occurs from last stream.
+         * @param construct Constructor for new output source. Should return a Writable or ReadWrite stream.
+         * @param demuxBy
+         * @param demuxBy.key? Key to fetch value from source chunks to demultiplex source.
+         * @param demuxBy.keyBy? Function to fetch value from source chunks to demultiplex source.
+         * @param options Writable stream options
+         */
+        demux: withDefaultOptions(2, demux),
+    };
 }
-
-/**
- * Unbatches and sends individual chunks of data.
- */
-export const unbatch = baseFunctions.unbatch;
-
-/**
- * Limits rate of data transferred into stream.
- * @param options?
- * @param targetRate? Desired rate in ms.
- * @param period? Period to sleep for when rate is above or equal to targetRate.
- */
-export function rate(targetRate?: number, period?: number): Transform {
-    return baseFunctions.rate(targetRate, period);
-}
-
-/**
- * Limits number of parallel processes in flight.
- * @param parallel Max number of parallel processes.
- * @param func Function to execute on each data chunk.
- * @param pause Amount of time to pause processing when max number of parallel processes are executing.
- */
-export const parallelMap = baseFunctions.parallelMap;
-
-/**
- * Accummulates and sends batches of data. Each chunk that flows into the stream is checked against items
- * in the buffer. How the buffer is mutated is based on 1 of 2 possible buffering strategies:
- * 	1. Sliding
- * 		- If the buffer is larger than the batchSize, the front of the buffer is popped to maintain
- * 		the batchSize. When no key is provided, the batchSize is effectively the buffer length. When
- * 		a key is provided, the batchSize is based on the value at that key. For example, given a key
- * 		of `timestamp` and a batchSize of 3000, each item in the buffer will be guaranteed to be
- * 		within 3000 timestamp units from the first element. This means that with a key, multiple elements
- * 		may be spliced off the front of the buffer. The buffer is then pushed into the stream.
- * 	2. Rolling
- * 		- If the buffer is larger than the batchSize, the buffer is cleared and pushed into the stream.
- * 		When no key is provided, the batchSize is the buffer length. When a key is provided, the batchSize
- * 		is based on the value at that key. For example, given a key of `timestamp` and a batchSize of 3000,
- * 		each item in the buffer will be guaranteed to be within 3000 timestamp units from the first element.
- * @param flushStrategy Buffering strategy to use.
- * @param batchSize Size of the batch (in units of buffer length or value at key).
- * @param batchRate Desired rate of data transfer to next stream.
- * @param keyBy Key to determine if element fits into buffer or items need to be cleared from buffer.
- * @param options Transform stream options
- */
-export const accumulator = baseFunctions.accumulator;
-
-/**
- * Accummulates and sends batches of data. Each chunk that flows into the stream is checked against items
- * in the buffer. How the buffer is mutated is based on 1 of 2 possible buffering strategies:
- * 	1. Sliding
- * 		- If the iteratee returns false, the front of the buffer is popped until iteratee returns true. The
- * 		item is pushed into the buffer and buffer is pushed into stream.
- * 	2. Rolling
- * 		- If the iteratee returns false, the buffer is cleared and pushed into stream. The item is
- * 		then pushed into the buffer.
- * @param flushStrategy Buffering strategy to use.
- * @param iteratee Function applied to buffer when a chunk of data enters stream to determine if element fits into
- * or items need to be cleared from buffer.
- * @param batchRate Desired rate of data transfer to next stream.
- * @param options Transform stream options
- */
-export const accumulatorBy = baseFunctions.accumulatorBy;
-
-/**
- * Composes multiple streams together. Writing occurs on first stream, piping occurs from last stream.
- * @param streams Array of streams to compose. Minimum of two.
- * @param options Transform stream options
- */
-export const compose = baseFunctions.compose;
-
-/**
- * Composes multiple streams together. Writing occurs on first stream, piping occurs from last stream.
- * @param construct Constructor for new output source. Should return a Writable or ReadWrite stream.
- * @param demuxBy
- * @param demuxBy.key? Key to fetch value from source chunks to demultiplex source.
- * @param demuxBy.keyBy? Function to fetch value from source chunks to demultiplex source.
- * @param options Writable stream options
- */
-export const demux = baseFunctions.demux;

src/functions/join.ts

@@ -1,10 +1,10 @@
-import { Transform } from "stream";
+import { Transform, TransformOptions } from "stream";
 import { StringDecoder } from "string_decoder";
 import { WithEncoding } from "./baseDefinitions";
 
 export function join(
     separator: string,
-    options: WithEncoding = { encoding: "utf8" },
+    options?: WithEncoding & TransformOptions,
 ): Transform {
     let isFirstChunk = true;
     const decoder = new StringDecoder(options.encoding);

src/functions/parallelMap.ts

@@ -4,10 +4,8 @@ import { sleep } from "../helpers";
 export function parallelMap<T, R>(
     mapper: (data: T) => R,
     parallel: number = 10,
-    sleepTime: number = 5,
+    sleepTime: number = 1,
-    options: TransformOptions = {
+    options?: TransformOptions,
-        objectMode: true,
-    },
 ) {
     let inflight = 0;
     return new Transform({

src/functions/rate.ts

@@ -5,13 +5,12 @@ import { sleep } from "../helpers";
 export function rate(
     targetRate: number = 50,
     period: number = 1,
-    options: TransformOptions = {
+    options?: TransformOptions,
-        objectMode: true,
-    },
 ): Transform {
     const deltaMS = ((1 / targetRate) * 1000) / period; // Skip a full period
     let total = 0;
     const start = performance.now();
+    console.log(options);
     return new Transform({
         ...options,
         async transform(data, encoding, callback) {

src/functions/reduce.ts

@@ -5,9 +5,7 @@ export function reduce<T, R>(
         | ((previousValue: R, chunk: T, encoding: string) => R)
         | ((previousValue: R, chunk: T, encoding: string) => Promise<R>),
     initialValue: R,
-    options: TransformOptions = {
+    options?: TransformOptions,
-        objectMode: true,
-    },
 ) {
     let value = initialValue;
     return new Transform({

src/functions/replace.ts

@@ -1,7 +1,6 @@
 import { Transform } from "stream";
 import { StringDecoder } from "string_decoder";
 import { WithEncoding } from "./baseDefinitions";
-
 export function replace(
     searchValue: string | RegExp,
     replaceValue: string,

src/functions/split.ts

@@ -2,6 +2,10 @@ import { Transform } from "stream";
 import { StringDecoder } from "string_decoder";
 import { WithEncoding } from "./baseDefinitions";
 
+interface SplitParams {
+    separator?: string | RegExp;
+    options?: WithEncoding;
+}
 export function split(
     separator: string | RegExp = "\n",
     options: WithEncoding = { encoding: "utf8" },

src/functions/unbatch.ts

@@ -1,10 +1,6 @@
 import { Transform, TransformOptions } from "stream";
 
-export function unbatch(
+export function unbatch(options?: TransformOptions) {
-    options: TransformOptions = {
-        objectMode: true,
-    },
-) {
     return new Transform({
         ...options,
         transform(data, encoding, callback) {

src/index.ts

@@ -1,26 +1,2 @@
-export {
+import mhysa from "./functions";
-    fromArray,
+export default mhysa;
-    map,
-    flatMap,
-    filter,
-    reduce,
-    split,
-    join,
-    replace,
-    parse,
-    stringify,
-    collect,
-    concat,
-    merge,
-    duplex,
-    child,
-    last,
-    batch,
-    unbatch,
-    rate,
-    parallelMap,
-    accumulator,
-    accumulatorBy,
-    compose,
-    demux,
-} from "./functions";

tests/accumulator.spec.ts

@@ -1,9 +1,10 @@
 import test from "ava";
 import { expect } from "chai";
 import { Readable } from "stream";
-import { accumulator, accumulatorBy } from "../src";
+import mhysa from "../src";
 import { FlushStrategy } from "../src/functions/accumulator";
 import { performance } from "perf_hooks";
+const { accumulator, accumulatorBy } = mhysa({ objectMode: true });
 
 test.cb("accumulator() rolling", t => {
     t.plan(3);

tests/batch.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { batch } from "../src";
+import mhysa from "../src";
+const { batch } = mhysa({ objectMode: true });
 
 test.cb("batch() batches chunks together", t => {
     t.plan(3);
@@ -31,7 +32,9 @@ test.cb("batch() yields a batch after the timeout", t => {
     t.plan(3);
     const source = new Readable({
         objectMode: true,
-        read(size: number) {},
+        read(size: number) {
+            return;
+        },
     });
     const expectedElements = [["a", "b"], ["c"], ["d"]];
     let i = 0;

tests/child.spec.ts

@@ -2,7 +2,8 @@ import * as cp from "child_process";
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { child } from "../src";
+import mhysa from "../src";
+const { child } = mhysa();
 
 test.cb(
     "child() allows easily writing to child process stdin and reading from its stdout",

tests/collect.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { collect } from "../src";
+import mhysa from "../src";
+const { collect } = mhysa();
 
 test.cb(
     "collect() collects streamed elements into an array (object, flowing mode)",

tests/compose.spec.ts

@@ -1,8 +1,9 @@
 const test = require("ava");
 const { expect } = require("chai");
-const { compose, map } = require("../src");
 const { sleep } = require("../src/helpers");
+import mhysa from "../src";
 import { performance } from "perf_hooks";
+const { compose, map } = mhysa({ objectMode: true });
 
 test.cb("compose() chains two streams together in the correct order", t => {
     t.plan(3);
@@ -211,7 +212,7 @@ test("compose() should emit drain event ~rate * highWaterMark ms for every write
             expect(composed._writableState.length).to.be.equal(0);
             expect(performance.now() - start).to.be.closeTo(
                 _rate * highWaterMark,
-                20,
+                40,
             );
         });
 
@@ -286,7 +287,7 @@ test.cb(
             expect(composed._writableState.length).to.be.equal(0);
             expect(performance.now() - start).to.be.closeTo(
                 _rate * input.length,
-                25,
+                50,
             );
             t.pass();
         });

tests/concat.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { concat, collect } from "../src";
+import mhysa from "../src";
+const { concat, collect } = mhysa();
 
 test.cb(
     "concat() concatenates multiple readable streams (object, flowing mode)",

tests/defaultOptions.spec.ts

@@ -0,0 +1,21 @@
+import { Readable } from "stream";
+import test from "ava";
+import mhysa from "../src";
+
+const withDefaultOptions = mhysa({ objectMode: true });
+const withoutOptions = mhysa();
+
+test("Mhysa instances can have default options", t => {
+    let batch = withDefaultOptions.batch();
+    t.true(batch._readableState.objectMode);
+    t.true(batch._writableState.objectMode);
+    batch = withDefaultOptions.batch(3);
+    t.true(batch._readableState.objectMode);
+    t.true(batch._writableState.objectMode);
+    batch = withDefaultOptions.batch(3, 1);
+    t.true(batch._readableState.objectMode);
+    t.true(batch._writableState.objectMode);
+    batch = withDefaultOptions.batch(3, 1, { objectMode: false });
+    t.false(batch._readableState.objectMode);
+    t.false(batch._writableState.objectMode);
+});

tests/demux.spec.ts

@@ -1,10 +1,11 @@
 import test from "ava";
 import { expect } from "chai";
-const { demux, map } = require("../src");
+import mhysa from "../src";
 import { Writable } from "stream";
 const sinon = require("sinon");
 const { sleep } = require("../src/helpers");
 import { performance } from "perf_hooks";
+const { demux, map } = mhysa();
 
 interface Test {
     key: string;

tests/duplex.spec.ts

@@ -2,7 +2,8 @@ import * as cp from "child_process";
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { duplex } from "../src";
+import mhysa from "../src";
+const { duplex } = mhysa();
 
 test.cb(
     "duplex() combines a writable and readable stream into a ReadWrite stream",

tests/filter.spec.ts

@@ -1,7 +1,8 @@
 import test from "ava";
 import { expect } from "chai";
 import { Readable } from "stream";
-import { filter } from "../src";
+import mhysa from "../src";
+const { filter } = mhysa();
 
 test.cb("filter() filters elements synchronously", t => {
     t.plan(2);

tests/flatMap.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { flatMap } from "../src";
+import mhysa from "../src";
+const { flatMap } = mhysa({ objectMode: true });
 
 test.cb("flatMap() maps elements synchronously", t => {
     t.plan(6);

tests/fromArray.spec.ts

@@ -1,6 +1,7 @@
 import test from "ava";
 import { expect } from "chai";
-import { fromArray } from "../src";
+import mhysa from "../src";
+const { fromArray } = mhysa();
 
 test.cb("fromArray() streams array elements in flowing mode", t => {
     t.plan(3);

tests/join.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { join } from "../src";
+import mhysa from "../src";
+const { join } = mhysa();
 
 test.cb("join() joins chunks using the specified separator", t => {
     t.plan(9);

tests/last.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { last } from "../src";
+import mhysa from "../src";
+const { last } = mhysa();
 
 test("last() resolves to the last chunk streamed by the given readable stream", async t => {
     const source = new Readable({ objectMode: true });

tests/map.spec.ts

@@ -1,12 +1,15 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { map } from "../src";
+import mhysa from "../src";
+const { map } = mhysa();
 
 test.cb("map() maps elements synchronously", t => {
     t.plan(3);
     const source = new Readable({ objectMode: true });
-    const mapStream = map((element: string) => element.toUpperCase());
+    const mapStream = map((element: string) => element.toUpperCase(), {
+        objectMode: true,
+    });
     const expectedElements = ["A", "B", "C"];
     let i = 0;
     source
@@ -28,10 +31,13 @@ test.cb("map() maps elements synchronously", t => {
 test.cb("map() maps elements asynchronously", t => {
     t.plan(3);
     const source = new Readable({ objectMode: true });
-    const mapStream = map(async (element: string) => {
+    const mapStream = map(
-        await Promise.resolve();
+        async (element: string) => {
-        return element.toUpperCase();
+            await Promise.resolve();
-    });
+            return element.toUpperCase();
+        },
+        { objectMode: true },
+    );
     const expectedElements = ["A", "B", "C"];
     let i = 0;
     source

tests/merge.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { merge } from "../src";
+import mhysa from "../src";
+const { merge } = mhysa();
 
 test.cb(
     "merge() merges multiple readable streams in chunk arrival order",

tests/parallelMap.spec.ts

@@ -2,8 +2,9 @@ import { Readable } from "stream";
 import { performance } from "perf_hooks";
 import test from "ava";
 import { expect } from "chai";
-import { parallelMap } from "../src";
+import mhysa from "../src";
 import { sleep } from "../src/helpers";
+const { parallelMap } = mhysa({ objectMode: true });
 
 test.cb("parallelMap() parallel mapping", t => {
     t.plan(6);

tests/parse.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { parse } from "../src";
+import mhysa from "../src";
+const { parse } = mhysa();
 
 test.cb("parse() parses the streamed elements as JSON", t => {
     t.plan(3);

tests/rate.spec.ts

@@ -2,7 +2,8 @@ import { Readable } from "stream";
 import { performance } from "perf_hooks";
 import test from "ava";
 import { expect } from "chai";
-import { rate } from "../src";
+import mhysa from "../src";
+const { rate } = mhysa({ objectMode: true });
 
 test.cb("rate() sends data at a rate of 150", t => {
     t.plan(5);

tests/reduce.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { reduce } from "../src";
+import mhysa from "../src";
+const { reduce } = mhysa({ objectMode: true });
 
 test.cb("reduce() reduces elements synchronously", t => {
     t.plan(1);

tests/replace.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { replace } from "../src";
+import mhysa from "../src";
+const { replace } = mhysa();
 
 test.cb(
     "replace() replaces occurrences of the given string in the streamed elements with the specified " +

tests/split.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { split } from "../src";
+import mhysa from "../src";
+const { split } = mhysa();
 
 test.cb("split() splits chunks using the default separator (\\n)", t => {
     t.plan(5);

tests/stringify.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { stringify } from "../src";
+import mhysa from "../src";
+const { stringify } = mhysa();
 
 test.cb("stringify() stringifies the streamed elements as JSON", t => {
     t.plan(4);

tests/unbatch.spec.ts

@@ -1,7 +1,8 @@
 import { Readable } from "stream";
 import test from "ava";
 import { expect } from "chai";
-import { unbatch, batch } from "../src";
+import mhysa from "../src";
+const { unbatch, batch } = mhysa({ objectMode: true });
 
 test.cb("unbatch() unbatches", t => {
     t.plan(3);
@@ -9,7 +10,7 @@ test.cb("unbatch() unbatches", t => {
     const expectedElements = ["a", "b", "c"];
     let i = 0;
     source
-        .pipe(batch(3))
+        .pipe(batch(3, undefined, { objectMode: true }))
         .pipe(unbatch())
         .on("data", (element: string) => {
             expect(element).to.equal(expectedElements[i]);