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Add every() and delay() methods back

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This commit is contained in:
Sami Turcotte 2018-11-26 01:18:01 -05:00
parent 6ea306536d
commit db3c0bd63e
5 changed files with 177 additions and 19 deletions
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52
README.md
View File

@ -1,6 +1,6 @@
# mysah
Promise, Stream and EventEmitter utils for Node.js
**Promise, Stream and EventEmitter utils for Node.js**
## Installation
@ -10,8 +10,10 @@ yarn add mysah
## Basic Usage
The following snippet demonstrates most of mysah's current features. More will come!
```js
const { once, sleep, stream } = require("mysah");
const { sleep, once, delay, every, stream } = require("mysah");
async function main() {
const collector = stream
@ -22,8 +24,16 @@ async function main() {
.pipe(stream.collect({ objectMode: true }));
const collected = await once(collector, "data");
console.log(collected); // [ 'a', 'b', 'c', 'd', 'e' ]
await sleep(1000); // Resolve after one second
await sleep(1000); // undefined (after one second)
await delay(collected, 1000); // [ 'a', 'b', 'c', 'd', 'e' ] (after another second)
await every(
[Promise.resolve("ab"), delay("cd", 1000)],
c => c.length === 2
); // true (after another second)
await every(
[Promise.resolve("ab"), delay("cd", 1000)],
c => c.length === 1
); // false (instantly)
}
main();
```
@ -65,14 +75,40 @@ export declare function concat(
/**
* Resolve after the given delay in milliseconds
*
* @param ms - The number of milliseconds to wait
* @param ms The number of milliseconds to wait
*/
export declare function sleep(ms: number): Promise<{}>;
/**
* Resolve a value after the given delay in milliseconds
*
* @param value Value to resolve
* @param ms Number of milliseconds to wait
*/
export declare function delay<T>(value: T, ms: number): Promise<T>;
/**
* Resolve once the given event emitter emits the specified event
*
* @param emitter - The event emitter to watch
* @param event - The event to watch
* @param emitter Event emitter to watch
* @param event Event to watch
*/
export declare function once<T>(emitter: NodeJS.EventEmitter, event: string): Promise<T>;
export declare function once<T>(
emitter: NodeJS.EventEmitter,
event: string,
): Promise<T>;
/**
* Resolve to false as soon as any of the promises has resolved to a value for which the predicate is
* falsey, or resolve to true when all of the promises have resolved to a value for which the predicate is
* thruthy, or rejects with the reason of the first promise rejection
*
* @param promises Promises whose resolved values will be tested by the predicate
* @param predicate Predicate to apply
* @returns Promise indicating whether the predicate holds for all resolved promise values
*/
export declare function every<T>(
promises: Array<Promise<T>>,
predicate: (value: T) => boolean,
): Promise<boolean>;
```

4
package.json
View File

@ -1,6 +1,6 @@
{
"name": "mysah",
"version": "0.3.4",
"version": "0.3.5",
"description": "Promise, Stream and EventEmitter utils for Node.js",
"keywords": [
"promise",
@ -34,7 +34,7 @@
"@types/node": "^10.12.10",
"ava": "^1.0.0-rc.2",
"chai": "^4.2.0",
"mysah": "^0.3.3",
"mysah": "0.2",
"prettier": "^1.14.3",
"ts-node": "^7.0.1",
"tslint": "^5.11.0",

55
src/utils.spec.ts
View File

@ -1,7 +1,7 @@
import test from "ava";
import { expect } from "chai";
import { EventEmitter } from "events";
import { once, sleep } from "./utils";
import { once, sleep, delay, every } from "./utils";
const TimingErrorMarginMs = 50;
@ -14,6 +14,16 @@ test("sleep() resolves after the specified delay in milliseconds", async t => {
expect(after - before).closeTo(200, TimingErrorMarginMs);
});
test("delay() resolves a value after the specified delay in milliseconds", async t => {
const before = Date.now();
const value = await delay("abc", 200);
const after = Date.now();
expect(value).equal("abc");
expect(after - before).gte(200);
expect(after - before).closeTo(200, TimingErrorMarginMs);
});
test("once() resolves only after the specified event is emitted", async t => {
const emitter = new EventEmitter();
const before = Date.now();
@ -23,7 +33,48 @@ test("once() resolves only after the specified event is emitted", async t => {
const result = await once(emitter, "done");
const after = Date.now();
expect(result).to.equal("some-result");
expect(result).equal("some-result");
expect(after - before).gte(200);
expect(after - before).closeTo(200, TimingErrorMarginMs);
});
test("every() resolves to true when the predicate holds true for all resolved values", async t => {
const before = Date.now();
const result = await every(
[Promise.resolve("a"), Promise.resolve("b"), delay("c", 200)],
() => true,
);
const after = Date.now();
expect(result).equal(true);
expect(after - before).gte(200);
expect(after - before).closeTo(200, TimingErrorMarginMs);
});
test("every() resolves to false as soon as the predicate does not hold for some resolved value", async t => {
const before = Date.now();
const result = await every(
[Promise.resolve("a"), Promise.resolve("bb"), delay("c", 200)],
(value: string) => value.length === 1,
);
const after = Date.now();
expect(result).equal(false);
expect(after - before).lt(200);
expect(after - before).closeTo(0, TimingErrorMarginMs);
});
test("every() rejects with the reason as soon as any of the promises rejects", async t => {
const before = Date.now();
await t.throwsAsync(() =>
every(
[
Promise.resolve("a"),
Promise.reject(new Error("Expected")),
delay("c", 200),
],
() => true,
),
);
const after = Date.now();
expect(after - before).lt(200);
expect(after - before).closeTo(0, TimingErrorMarginMs);
});

63
src/utils.ts
View File

@ -1,7 +1,7 @@
/**
* Resolve after the given delay in milliseconds
*
* @param ms - The number of milliseconds to wait
* @param ms The number of milliseconds to wait
*/
export function sleep(ms: number) {
return new Promise(resolve => {
@ -9,11 +9,23 @@ export function sleep(ms: number) {
});
}
/**
* Resolve a value after the given delay in milliseconds
*
* @param value Value to resolve
* @param ms Number of milliseconds to wait
*/
export function delay<T>(value: T, ms: number): Promise<T> {
return new Promise(resolve => {
setTimeout(() => resolve(value), ms);
});
}
/**
* Resolve once the given event emitter emits the specified event
*
* @param emitter - The event emitter to watch
* @param event - The event to watch
* @param emitter Event emitter to watch
* @param event Event to watch
*/
export function once<T>(
emitter: NodeJS.EventEmitter,
@ -25,3 +37,48 @@ export function once<T>(
});
});
}
/**
* Resolve to false as soon as any of the promises has resolved to a value for which the predicate is
* falsey, or resolve to true when all of the promises have resolved to a value for which the predicate is
* thruthy, or rejects with the reason of the first promise rejection
*
* @param promises Promises whose resolved values will be tested by the predicate
* @param predicate Predicate to apply
* @returns Promise indicating whether the predicate holds for all resolved promise values
*/
export function every<T>(
promises: Array<Promise<T>>,
predicate: (value: T) => boolean,
): Promise<boolean> {
if (promises.length > 0) {
return new Promise((resolve, reject) => {
let resolvedCount = 0;
let done = false;
promises.forEach(promise => {
promise
.then(value => {
resolvedCount++;
if (!done) {
const predicateValue = predicate(value);
if (!predicateValue) {
resolve(false);
done = true;
} else if (resolvedCount === promises.length) {
resolve(predicateValue);
done = true;
}
}
})
.catch(err => {
if (!done) {
reject(err);
done = true;
}
});
});
});
} else {
return Promise.resolve(true);
}
}

22
yarn.lock
View File

@ -1142,6 +1142,18 @@ es6-error@^4.0.1:
resolved "https://registry.yarnpkg.com/es6-error/-/es6-error-4.1.1.tgz#9e3af407459deed47e9a91f9b885a84eb05c561d"
integrity sha512-Um/+FxMr9CISWh0bi5Zv0iOD+4cFh5qLeks1qhAopKVAJw3drgKbKySikp7wGhDL0HPeaja0P5ULZrxLkniUVg==
es6-promise@^4.0.3:
version "4.2.5"
resolved "https://registry.yarnpkg.com/es6-promise/-/es6-promise-4.2.5.tgz#da6d0d5692efb461e082c14817fe2427d8f5d054"
integrity sha512-n6wvpdE43VFtJq+lUDYDBFUwV8TZbuGXLV4D6wKafg13ldznKsyEvatubnmUe31zcvelSzOHF+XbaT+Bl9ObDg==
es6-promisify@^5.0.0:
version "5.0.0"
resolved "https://registry.yarnpkg.com/es6-promisify/-/es6-promisify-5.0.0.tgz#5109d62f3e56ea967c4b63505aef08291c8a5203"
integrity sha1-UQnWLz5W6pZ8S2NQWu8IKRyKUgM=
dependencies:
es6-promise "^4.0.3"
escape-string-regexp@^1.0.2, escape-string-regexp@^1.0.4, escape-string-regexp@^1.0.5:
version "1.0.5"
resolved "https://registry.yarnpkg.com/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz#1b61c0562190a8dff6ae3bb2cf0200ca130b86d4"
@ -2158,10 +2170,12 @@ multimatch@^2.1.0:
arrify "^1.0.0"
minimatch "^3.0.0"
mysah@^0.3.3:
version "0.3.3"
resolved "https://registry.yarnpkg.com/mysah/-/mysah-0.3.3.tgz#4fd0c0489e9f9f99898d1584b73357f5a60a1dda"
integrity sha512-hiottniB9LFmN6I4SL7VJtz7ahi9w0ndE4PJel7WZ6ovvA1LHRJVmbYTbRsy24rHD762ahwLYadxpDE9j+2K+A==
mysah@0.2:
version "0.2.0"
resolved "https://registry.yarnpkg.com/mysah/-/mysah-0.2.0.tgz#77bcaaa25829bf874ac40ee5c47069bcf52e7283"
integrity sha1-d7yqolgpv4dKxA7lxHBpvPUucoM=
dependencies:
es6-promisify "^5.0.0"
nan@^2.9.2:
version "2.11.1"