Merge branch 'dev' into master

This commit is contained in:
Lewis Diamond 2020-08-05 10:42:33 -04:00
commit fc5b96f725
33 changed files with 322 additions and 96 deletions

138
README.md
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@ -2,11 +2,14 @@
**Dependency-free stream utils for Node.js**
<sub>Released under the [MIT](https://git.lewis.id/strom/blob/master/LICENSE) license.</sub>
<sub>Released under the [MIT](LICENSE) license.</sub>
```sh
yarn add stromjs
```
```sh
npm add stromjs
```
## fromArray(array)
Convert an array into a `Readable` stream of its elements
@ -23,7 +26,7 @@ strom.fromArray(["a", "b"])
## map(mapper, options)
Return a `ReadWrite` stream that maps streamed chunks
Returns a `ReadWrite` stream that maps streamed chunks
| Param | Type | Description |
| --- | --- | --- |
@ -41,7 +44,7 @@ strom.fromArray(["a", "b"])
## flatMap(mapper, options)
Return a `ReadWrite` stream that flat maps streamed chunks
Returns a `ReadWrite` stream that flat maps streamed chunks
| Param | Type | Description |
| --- | --- | --- |
@ -59,7 +62,7 @@ strom.fromArray(["a", "AA"])
## filter(predicate, options)
Return a `ReadWrite` stream that filters out streamed chunks for which the predicate does not hold
Returns a `ReadWrite` stream that filters out streamed chunks for which the predicate does not hold
| Param | Type | Description |
| --- | --- | --- |
@ -76,7 +79,7 @@ strom.fromArray(["a", "b", "c"])
## reduce(iteratee, initialValue, options)
Return a `ReadWrite` stream that reduces streamed chunks down to a single value and yield that
Returns a `ReadWrite` stream that reduces streamed chunks down to a single value and yield that
value
| Param | Type | Description |
@ -97,7 +100,7 @@ strom.fromArray(["a", "b", "cc"])
## split(separator)
Return a `ReadWrite` stream that splits streamed chunks using the given separator
Returns a `ReadWrite` stream that splits streamed chunks using the given separator
| Param | Type | Description |
| --- | --- | --- |
@ -115,7 +118,7 @@ strom.fromArray(["a,b", "c,d"])
## join(separator)
Return a `ReadWrite` stream that joins streamed chunks using the given separator
Returns a `ReadWrite` stream that joins streamed chunks using the given separator
| Param | Type | Description |
| --- | --- | --- |
@ -132,7 +135,7 @@ strom.fromArray(["a", "b", "c"])
## replace(searchValue, replaceValue)
Return a `ReadWrite` stream that replaces occurrences of the given string or regular expression in
Returns a `ReadWrite` stream that replaces occurrences of the given string or regular expression in
the streamed chunks with the specified replacement string
| Param | Type | Description |
@ -151,7 +154,7 @@ strom.fromArray(["a1", "b22", "c333"])
## parse()
Return a `ReadWrite` stream that parses the streamed chunks as JSON
Returns a `ReadWrite` stream that parses the streamed chunks as JSON
```js
strom.fromArray(['{ "a": "b" }'])
@ -162,7 +165,7 @@ strom.fromArray(['{ "a": "b" }'])
## stringify()
Return a `ReadWrite` stream that stringifies the streamed chunks to JSON
Returns a `ReadWrite` stream that stringifies the streamed chunks to JSON
```js
strom.fromArray([{ a: "b" }])
@ -173,7 +176,7 @@ strom.fromArray([{ a: "b" }])
## collect(options)
Return a `ReadWrite` stream that collects streamed chunks into an array or buffer
Returns a `ReadWrite` stream that collects streamed chunks into an array or buffer
| Param | Type | Description |
| --- | --- | --- |
@ -189,7 +192,7 @@ strom.fromArray(["a", "b", "c"])
## concat(streams)
Return a `Readable` stream of readable streams concatenated together
Returns a `Readable` stream of readable streams concatenated together
| Param | Type | Description |
| --- | --- | --- |
@ -210,7 +213,7 @@ source2.push(null);
## merge(streams)
Return a `Readable` stream of readable streams merged together in chunk arrival order
Returns a `Readable` stream of readable streams merged together in chunk arrival order
| Param | Type | Description |
| --- | --- | --- |
@ -231,7 +234,7 @@ setTimeout(() => source2.push(null), 50);
## duplex(writable, readable)
Return a `Duplex` stream from a writable stream that is assumed to somehow, when written to,
Returns a `Duplex` stream from a writable stream that is assumed to somehow, when written to,
cause the given readable stream to yield chunks
| Param | Type | Description |
@ -249,7 +252,7 @@ strom.fromArray(["a", "b", "c"])
## child(childProcess)
Return a `Duplex` stream from a child process' stdin and stdout
Returns a `Duplex` stream from a child process' stdin and stdout
| Param | Type | Description |
| --- | --- | --- |
@ -265,7 +268,7 @@ strom.fromArray(["a", "b", "c"])
## last(readable)
Return a `Promise` resolving to the last streamed chunk of the given readable stream, after it has
Returns a `Promise` resolving to the last streamed chunk of the given readable stream, after it has
ended
| Param | Type | Description |
@ -280,3 +283,106 @@ let f = async () => {
f();
// c is printed out
```
## accumulator(flushStrategy, iteratee, options)
TO BE DOCUMENTED
## batch(batchSize, maxBatchAge, options)
Returns a `Transform` stream which produces all incoming data in batches of size `batchSize`.
| Param | Type | Description |
| --- | --- | --- |
| `batchSize` | `number` | Size of the batches to be produced |
| `maxBatchAge` | `number` | Maximum number of milliseconds a message will be queued for. E.g. a batch will be produced before reaching `batchSize` if the first message queued is `maxBatchAge` ms old or more |
| `options` | `TransformOptions` | Options passed down to the Transform object |
```js
strom.fromArray(["a", "b", "c", "d"])
.pipe(strom.batch(3, 500))
.pipe(process.stdout);
// ["a","b","c"]
// ["d"] //After 500ms
```
## compose(streams, errorCb, options)
Returns a `Transform` stream which consists of all `streams` but behaves as a single stream. The returned stream can be piped into and from transparently.
| Param | Type | Description |
| --- | --- | --- |
| `streams` | `Array` | Streams to be composed |
| `errorCb` | `(err: Error) => void` | Function called when an error occurs in any of the streams |
| `options` | `TransformOptions` | Options passed down to the Transform object |
```js
const composed = strom.compose([
strom.split(),
strom.map(data => data.trim()),
strom.filter(str => !!str),
strom.parse(),
strom.flatMap(data => data),
strom.stringify(),
]);
const data = ["[1,2,3] \n [4,5,6] ", "\n [7,8,9] \n\n"];
strom.fromArray(data).pipe(composed).pipe(process.stdout);
// 123456789
```
## demux(pipelineConstructor, demuxBy, options)
TO BE DOCUMENTED
## parallelMap(mapper, parallel, sleepTime, options)
Returns a `Transform` stream which maps incoming data through the async mapper with the given parallelism.
| Param | Type | Description | Default |
| --- | --- | --- | --- |
| `mapper` | `async (chunk: T, encoding: string) => R` | Mapper function, mapping each (chunk, encoding) to a new chunk (non-async will not be parallelized) | -- |
| `parallel` | `number` | Number of concurrent executions of the mapper allowed | 10 |
| `sleepTime` | `number` | Number of milliseconds to wait before testing if more messages can be processed | 1 |
```js
function sleep(time) {
return time > 0 ? new Promise(resolve => setTimeout(resolve, time)) : null;
}
strom
.fromArray([1, 2, 3, 4, 6, 8])
.pipe(
strom.parallelMap(async d => {
await sleep(10000 - d * 1000);
return `${d}`;
}, 3),
)
.pipe(process.stdout);
// 321864
```
## rate()
```js
const strom = require("stromjs").strom();
function sleep(time) {
return time > 0 ? new Promise(resolve => setTimeout(resolve, time)) : null;
}
const rate = strom.rate(2, 1, { behavior: 1 });
rate.pipe(strom.map(x => console.log(x)));
async function produce() {
rate.write(1);
await sleep(500);
rate.write(2);
await sleep(500);
rate.write(3);
rate.write(4);
rate.write(5);
await sleep(500);
rate.write(6);
}
produce();
```

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@ -1,6 +1,6 @@
{
"name": "stromjs",
"version": "2.0.0-alpha.1",
"version": "0.5.1",
"description": "Dependency-free streams utils for Node.js",
"keywords": [
"promise",
@ -9,10 +9,18 @@
],
"contributors": [
{
"name": "Wenzil"
"name": "Sami Turcotte",
"url": "https://github.com/Wenzil"
},
{
"name": "Lewis Diamond"
"name": "Jerry Kurian",
"email": "jerrykurian@protonmail.com",
"url": "https://github.com/jkurian"
},
{
"name": "Lewis Diamond",
"email": "stromjs@lewisdiamond.com",
"url": "https://github.com/lewisdiamond"
}
],
"license": "MIT",

15
samples/parallelMap.js Normal file
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@ -0,0 +1,15 @@
const strom = require("stromjs").strom();
function sleep(time) {
return time > 0 ? new Promise(resolve => setTimeout(resolve, time)) : null;
}
strom
.fromArray([1, 2, 3, 4, 6, 8])
.pipe(
strom.parallelMap(async d => {
await sleep(10000 - d * 1000);
return `${d}`;
}, 3),
)
.pipe(process.stdout);

21
samples/rate.js Normal file
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@ -0,0 +1,21 @@
const strom = require("../dist/index.js");
function sleep(time) {
return time > 0 ? new Promise(resolve => setTimeout(resolve, time)) : null;
}
const rate = strom.rate(2, 1, { behavior: 1 });
rate.pipe(strom.map(x => console.log(x)));
async function produce() {
rate.write(1);
await sleep(500);
rate.write(2);
await sleep(500);
rate.write(3);
rate.write(4);
rate.write(5);
await sleep(500);
rate.write(6);
}
produce();

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@ -2,7 +2,7 @@ import { Transform, TransformOptions } from "stream";
export function batch(
batchSize: number = 1000,
maxBatchAge: number = 500,
maxBatchAge: number = 0,
options: TransformOptions = {},
): Transform {
let buffer: any[] = [];
@ -23,7 +23,7 @@ export function batch(
buffer.push(chunk);
if (buffer.length === batchSize) {
sendChunk(this);
} else {
} else if (maxBatchAge) {
if (timer === null) {
timer = setInterval(() => {
sendChunk(this);

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@ -263,5 +263,10 @@ export function strom(defaultOptions: TransformOptions = { objectMode: true }) {
* @param options Writable stream options
*/
demux: withDefaultOptions(2, demux),
/**
* Create a new strom instance overriding the defaults
*/
instance: strom,
};
}

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@ -2,21 +2,42 @@ import { Transform, TransformOptions } from "stream";
import { performance } from "perf_hooks";
import { sleep } from "../helpers";
export enum Behavior {
BUFFER = 0,
DROP = 1,
}
export interface RateOptions {
window?: number;
behavior?: Behavior;
}
export function rate(
targetRate: number = 50,
period: number = 1,
options?: TransformOptions,
options?: TransformOptions & RateOptions,
): Transform {
const deltaMS = ((1 / targetRate) * 1000) / period; // Skip a full period
let total = 0;
const start = performance.now();
const window = options?.window || Infinity;
const behavior = options?.behavior || Behavior.BUFFER;
let start = performance.now();
return new Transform({
...options,
async transform(data, encoding, callback) {
const currentRate = (total / (performance.now() - start)) * 1000;
const now = performance.now();
if (now - start >= window) {
start = now - window;
}
const currentRate = (total / (now - start)) * 1000;
if (targetRate && currentRate > targetRate) {
if (behavior === Behavior.DROP) {
callback(undefined);
return;
} else {
await sleep(deltaMS);
}
}
total += 1;
callback(undefined, data);
},

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@ -1,2 +1,29 @@
export { strom } from "./functions";
import { strom } from "./functions";
export * from "./utils";
export const {
fromArray,
map,
flatMap,
filter,
reduce,
split,
join,
replace,
parse,
stringify,
collect,
concat,
merge,
duplex,
child,
last,
batch,
unbatch,
rate,
parallelMap,
accumulator,
accumulatorBy,
compose,
demux,
instance,
} = strom();

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

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@ -1,8 +1,7 @@
import { Readable } from "stream";
import test from "ava";
import { expect } from "chai";
import { strom } from "../src";
const { batch, map, fromArray } = strom({ objectMode: true });
import { batch, map, fromArray } from "../src";
test.cb("batch() batches chunks together", t => {
t.plan(3);
@ -39,7 +38,7 @@ test.cb("batch() yields a batch after the timeout", t => {
const expectedElements = [["a", "b"], ["c"], ["d"]];
let i = 0;
source
.pipe(batch(3))
.pipe(batch(3, 500))
.on("data", (element: string[]) => {
t.deepEqual(element, expectedElements[i]);
i++;

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

View File

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

View File

@ -2,9 +2,8 @@ import * as test from "ava";
import { expect } from "chai";
import { sleep } from "../src/helpers";
import { Readable, Writable } from "stream";
import { strom } from "../src";
import { compose, map, fromArray } from "../src";
import { performance } from "perf_hooks";
const { compose, map, fromArray } = strom({ objectMode: true });
test.cb("compose() chains two streams together in the correct order", t => {
t.plan(3);

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

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@ -1,21 +1,30 @@
import { Readable } from "stream";
import test from "ava";
import { strom } from "../src";
import { batch as _batch, instance as strom } from "../src";
const withDefaultOptions = strom({ objectMode: true });
const withoutOptions = strom();
const withDefaultOptions = strom({ objectMode: false });
test("strom instances can have default options", t => {
let batch = withDefaultOptions.batch();
t.true(batch._readableState.objectMode);
t.true(batch._writableState.objectMode);
t.false(batch._readableState.objectMode);
t.false(batch._writableState.objectMode);
batch = withDefaultOptions.batch(3);
t.true(batch._readableState.objectMode);
t.true(batch._writableState.objectMode);
t.false(batch._readableState.objectMode);
t.false(batch._writableState.objectMode);
batch = withDefaultOptions.batch(3, 1);
t.false(batch._readableState.objectMode);
t.false(batch._writableState.objectMode);
batch = withDefaultOptions.batch(3, 1, { objectMode: true });
t.true(batch._readableState.objectMode);
t.true(batch._writableState.objectMode);
batch = withDefaultOptions.batch(3, 1, { objectMode: false });
batch = _batch(3);
t.true(batch._readableState.objectMode);
t.true(batch._writableState.objectMode);
batch = _batch(3, 1);
t.true(batch._readableState.objectMode);
t.true(batch._writableState.objectMode);
batch = _batch(3, 1, { objectMode: false });
t.false(batch._readableState.objectMode);
t.false(batch._writableState.objectMode);
});

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

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

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

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

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

View File

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

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

View File

@ -1,8 +1,7 @@
import { Readable } from "stream";
import test from "ava";
import { expect } from "chai";
import { strom } from "../src";
const { map } = strom();
import { map } from "../src";
test.cb("map() maps elements synchronously", t => {
t.plan(3);

View File

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

View File

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

View File

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

View File

@ -1,12 +1,11 @@
import { Readable } from "stream";
import { performance } from "perf_hooks";
import test from "ava";
import { expect } from "chai";
import { strom } from "../src";
const { rate } = strom({ objectMode: true });
import { rate } from "../src";
import { sleep } from "../src/helpers";
test.cb("rate() sends data at a rate of 150", t => {
t.plan(5);
t.plan(15);
const targetRate = 150;
const source = new Readable({ objectMode: true });
const expectedElements = ["a", "b", "c", "d", "e"];
@ -15,10 +14,10 @@ test.cb("rate() sends data at a rate of 150", t => {
source
.pipe(rate(targetRate))
.on("data", (element: string[]) => {
.on("data", (element: string) => {
const currentRate = (i / (performance.now() - start)) * 1000;
expect(element).to.deep.equal(expectedElements[i]);
expect(currentRate).lessThan(targetRate);
t.is(element, expectedElements[i]);
t.true(currentRate <= targetRate);
t.pass();
i++;
})
@ -34,7 +33,7 @@ test.cb("rate() sends data at a rate of 150", t => {
});
test.cb("rate() sends data at a rate of 50", t => {
t.plan(5);
t.plan(15);
const targetRate = 50;
const source = new Readable({ objectMode: true });
const expectedElements = ["a", "b", "c", "d", "e"];
@ -43,10 +42,10 @@ test.cb("rate() sends data at a rate of 50", t => {
source
.pipe(rate(targetRate))
.on("data", (element: string[]) => {
.on("data", (element: string) => {
const currentRate = (i / (performance.now() - start)) * 1000;
expect(element).to.deep.equal(expectedElements[i]);
expect(currentRate).lessThan(targetRate);
t.is(element, expectedElements[i]);
t.true(currentRate <= targetRate);
t.pass();
i++;
})
@ -62,7 +61,7 @@ test.cb("rate() sends data at a rate of 50", t => {
});
test.cb("rate() sends data at a rate of 1", t => {
t.plan(5);
t.plan(15);
const targetRate = 1;
const source = new Readable({ objectMode: true });
const expectedElements = ["a", "b", "c", "d", "e"];
@ -71,10 +70,10 @@ test.cb("rate() sends data at a rate of 1", t => {
source
.pipe(rate(targetRate))
.on("data", (element: string[]) => {
.on("data", (element: string) => {
const currentRate = (i / (performance.now() - start)) * 1000;
expect(element).to.deep.equal(expectedElements[i]);
expect(currentRate).lessThan(targetRate);
t.is(element, expectedElements[i]);
t.true(currentRate <= targetRate);
t.pass();
i++;
})
@ -88,3 +87,41 @@ test.cb("rate() sends data at a rate of 1", t => {
source.push("e");
source.push(null);
});
test("rate() sends data at a rate of 1 and drops extra messages", async t => {
t.plan(9);
const targetRate = 1;
const source = new Readable({
objectMode: true,
read: () => {
return;
},
});
const expectedElements = ["a", "b", "e"];
const start = performance.now();
let i = 0;
let plan = 0;
source
.pipe(rate(targetRate, 1, { behavior: 1 }))
.on("data", (element: string) => {
const currentRate = (i / (performance.now() - start)) * 1000;
t.is(element, expectedElements[i]);
t.true(currentRate <= targetRate);
plan++;
t.pass();
i++;
})
.on("error", t.fail)
.on("end", t.fail);
source.push("a");
await sleep(1000);
source.push("b");
source.push("c");
source.push("d");
await sleep(1000);
source.push("e");
await sleep(1000);
source.push(null);
});

View File

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

View File

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

View File

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

View File

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

View File

@ -1,8 +1,7 @@
import { Readable } from "stream";
import test from "ava";
import { expect } from "chai";
import { strom } from "../src";
const { unbatch, batch } = strom({ objectMode: true });
import { unbatch, batch } from "../src";
test.cb("unbatch() unbatches", t => {
t.plan(3);

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@ -1,7 +1,6 @@
import test from "ava";
import { collected } from "../../src/utils";
import { strom } from "../../src";
const { fromArray, collect } = strom({ objectMode: true });
import { fromArray, collect } from "../../src";
test("collected returns a promise for the first data point", async t => {
const data = collected(fromArray([1, 2, 3, 4]).pipe(collect()));