JsExt

Additional functions for JavaScript to build strong applications.

Import

// Node.js
import jsext from "@ayonli/jsext";

// Deno
import jsext from "https://lib.deno.dev/x/ayonli_jsext@latest/index.ts";

// Browser
import jsext from "https://lib.deno.dev/x/ayonli_jsext@latest/esm/index.js";

There is also a bundled version that can be loaded via a <script> tag in the browser.

<script src="https://lib.deno.dev/x/ayonli_jsext@latest/bundle/index.js"></script>
<script>
    const jsext = window["@ayonli/jsext"];
    // this will also include the sub-packages and augmentations
<script>

Functions

• jsext.try Call a function safely and return errors when captured.
• jsext.func Define a function along with a defer keyword, inspired by Golang.
• jsext.wrap Wrap a function for decorator pattern but keep its signature.
• jsext.throttle Throttle function calls for frequent access.
• jsext.queue Handle tasks sequentially and prevent concurrency conflicts.
• jsext.mixins Define a class that inherits methods from multiple base classes.
• jsext.isSubclassOf Check if a class is a subset of another class.
• jsext.read Make any streaming source readable via for await ... of ... syntax.
• jsext.readAll Read all streaming data at once.
• jsext.chan Create a channel that transfers data across routines, even between multiple threads, inspired by Golang.
• jsext.parallel Run functions in parallel threads and take advantage of multi-core CPUs, inspired by Golang.
• jsext.run Run a script in another thread and abort at any time.
• jsext.example Write unit tests as if writing examples, inspired by Golang.
• jsext.deprecate Mark a function as deprecated and emit warnings when it is called.

And other functions in sub-packages.

jsext.try

function _try<E = unknown, R = any, A extends any[] = any[]>(
    fn: (...args: A) => R,
    ...args: A
): [E, R];
function _try<E = unknown, R = any, A extends any[] = any[]>(
    fn: (...args: A) => Promise<R>,
    ...args: A
): Promise<[E, R]>;

Invokes a regular function or an async function and renders its result in an [err, res] tuple.

Example (regular function)

const [err, res] = _try(() => {
    // do something that may fail
});

Example (async function)

let [err, res] = await _try(async () => {
    return await axios.get("https://example.org");
});

if (err) {
    res = (err as any)["response"];
}

function _try<E = unknown, R = any>(job: Promise<R>): Promise<[E, R]>;

Resolves a promise and renders its result in an [err, res] tuple.

Example (promise)

let [err, res] = await _try(axios.get("https://example.org"));

if (err) {
    res = (err as any)["response"];
}

function _try<E = unknown, T = any, A extends any[] = any[], TReturn = any, TNext = unknown>(
    fn: (...args: A) => Generator<T, TReturn, TNext>,
    ...args: A
): Generator<[E, T], [E, TReturn], TNext>;
function _try<E = unknown, T = any, A extends any[] = any[], TReturn = any, TNext = unknown>(
    fn: (...args: A) => AsyncGenerator<T, TReturn, TNext>,
    ...args: A
): AsyncGenerator<[E, T], [E, TReturn], TNext>;

Invokes a generator function or an async generator function and renders its yield value and result in an [err, val] tuple.

Example (generator function)

const iter = _try(function* () {
    // do something that may fail
});

for (const [err, val] of iter) {
    if (err) {
        console.error("something went wrong:", err);
    } else {
        console.log("current value:", val);
    }
}

Example (async generator function)

const iter = _try(async function* () {
    // do something that may fail
});

for await (const [err, val] of iter) {
    if (err) {
        console.error("something went wrong:", err);
    } else {
        console.log("current value:", val);
    }
}

function _try<E = unknown, T = any, TReturn = any, TNext = unknown>(
    gen: Generator<T, TReturn, TNext>
): Generator<[E, T], [E, TReturn], TNext>;
function _try<E = unknown, T = any, TReturn = any, TNext = unknown>(
    gen: AsyncGenerator<T, TReturn, TNext>
): AsyncGenerator<[E, T], [E, TReturn], TNext>;

Resolves a generator or an async generator and renders its yield value and result in an [err, val] tuple.

Example (generator)

const iter = Number.sequence(1, 10);

for (const [err, val] of _try(iter)) {
    if (err) {
        console.error("something went wrong:", err);
    } else {
        console.log("current value:", val);
    }
}

Example (async generator)

async function* gen() {
    // do something that may fail
};

for await (const [err, val] of _try(gen())) {
    if (err) {
        console.error("something went wrong:", err);
    } else {
        console.log("current value:", val);
    }
}

jsext.func

function func<T, R = any, A extends any[] = any[]>(
    fn: (this: T, defer: (cb: () => void) => void, ...args: A) => R
): (this: T, ...args: A) => R;

Inspired by Golang, creates a function that receives a defer keyword which can be used to carry deferred jobs that will be run after the main function is complete.

Multiple calls of the defer keyword is supported, and the callbacks are called in the LIFO order. Callbacks can be async functions if the main function is an async function or an async generator function, and all the running procedures will be awaited.

Example

const getVersion = func(async (defer) => {
    const file = await fs.open("./package.json", "r");
    defer(() => file.close());

    const content = await file.readFile("utf8");
    const pkg = JSON.parse(content);

    return pkg.version as string;
});

jsext.wrap

function wrap<T, Fn extends (this: T, ...args: any[]) => any>(
    fn: Fn,
    wrapper: (this: T, fn: Fn, ...args: Parameters<Fn>) => ReturnType<Fn>
): Fn

Wraps a function inside another function and returns a new function that copies the original function's name and other properties.

Example

function log(text: string) {
    console.log(text);
}

const show = wrap(log, function (fn, text) {
    return fn.call(this, new Date().toISOString() + " " + text);
});

console.log(show.name); // log
console.log(show.length); // 1
console.assert(show.toString() === log.toString());

jsext.throttle

function throttle<T, Fn extends (this: T, ...args: any[]) => any>(
    handler: Fn,
    duration: number
): Fn;
function throttle<T, Fn extends (this: T, ...args: any[]) => any>(handler: Fn, options: {
    duration: number;
    /**
     * Use the throttle strategy `for` the given key, this will keep the result in a global
     * cache, binding new `handler` function for the same key will result in the same result
     * as the previous, unless the duration has passed. This mechanism guarantees that both
     * creating the throttled function in function scopes and overwriting the handler are
     * possible.
     */
    for?: any;
    /**
     * When turned on, respond with the last cache (if available) immediately, even if it has
     * expired, and update the cache in the background.
     */
    noWait?: boolean;
}): Fn;

Creates a throttled function that will only be run once in a certain amount of time.

If a subsequent call happens within the duration (in milliseconds), the previous result will be returned and the handler function will not be invoked.

Example

const fn = throttle((input: string) => input, 1_000);
console.log(fn("foo")); // foo
console.log(fn("bar")); // foo

await Promise.sleep(1_000);
console.log(fn("bar")); // bar

Example (with key)

const out1 = await throttle(() => Promise.resolve("foo"), { duration: 1_000, for: "example" })();
console.log(out1); // foo

const out2 = await throttle(() => Promise.resolve("bar"), { duration: 1_000, for: "example" })();
console.log(out2); // foo

await Promise.sleep(1_000);
const out3 = await throttle(() => Promise.resolve("bar"), { duration: 1_000, for: "example" })();
console.log(out3); // bar

jsext.queue

function queue<T>(handler: (data: T) => Promise<void>, bufferSize?: number): Queue<T>

Processes data sequentially by the given handler function and prevents concurrency conflicts, it returns a Queue instance that we can push data into.

bufferSize is the maximum capacity of the underlying channel, once reached, the push operation will block until there is new space available. Bu default, this option is not set and use a non-buffered channel instead.

Example

const list: string[] = [];
const q = queue(async (str: string) => {
    await Promise.resolve(null);
    list.push(str);
});

q.onError(err => {
    console.error(err);
});

await q.push("foo");
await q.push("foo");

console.log(list.length);
q.close();
// output:
// 2

jsext.mixins

function mixins<T extends Constructor<any>, M extends any[]>(
    base: T,
    ...mixins: { [X in keyof M]: Constructor<M[X]> }
): T & Constructor<UnionToIntersection<FlatArray<M, 1>>>;
function mixins<T extends Constructor<any>, M extends any[]>(
    base: T,
    ...mixins: M
): T & Constructor<UnionToIntersection<FlatArray<M, 1>>>;

Returns an extended class that combines all mixin methods.

This function does not mutates the base class but create a pivot class instead.

Example

class Log {
    log(text: string) {
        console.log(text);
    }
}

class View {
    display(data: Record<string, any>[]) {
        console.table(data);
    }
}

class Controller extends mixins(View, Log) {
    constructor(readonly topic: string) {
        super();
    }
}

const ctrl = new Controller("foo");
ctrl.log("something is happening");
ctrl.display([{ topic: ctrl.topic, content: "something is happening" }]);

console.assert(isSubclassOf(Controller, View));
console.assert(!isSubclassOf(Controller, Log));

jsext.isSubclassOf

function isSubclassOf<T, B>(ctor1: Constructor<T>, ctor2: Constructor<B>): boolean;

Checks if a class is a subclass of another class.

Example

class Moment extends Date {}

console.assert(isSubclassOf(Moment, Date));
console.assert(isSubclassOf(Moment, Object)); // all classes are subclasses of Object

jsext.read

function read<I extends AsyncIterable<any>>(iterable: I): I;
function read(es: EventSource, options?: { event?: string; }): AsyncIterable<string>;
function read<T extends Uint8Array | string>(ws: WebSocket): AsyncIterable<T>;
function read<T>(target: EventTarget, eventMap?: {
    message?: string;
    error?: string;
    close?: string;
}): AsyncIterable<T>;
function read<T>(target: NodeJS.EventEmitter, eventMap?: {
    data?: string;
    error?: string;
    close?: string;
}): AsyncIterable<T>;

Wraps a source as an AsyncIterable object that can be used in the for await...of... loop for reading streaming data.

Example (EventSource)

// listen to the `onmessage`
const sse = new EventSource("/sse/message");

for await (const msg of read(sse)) {
    console.log("receive message:", msg);
}

// listen to a specific event
const channel = new EventSource("/sse/broadcast");

for await (const msg of read(channel, { event: "broadcast" })) {
    console.log("receive message:", msg);
}

Example (WebSocket)

const ws = new WebSocket("/ws");

for await (const data of read(ws)) {
    if (typeof data === "string") {
        console.log("receive text message:", data);
    } else {
        console.log("receive binary data:", data);
    }
}

Example (EventTarget)

for await (const msg of read(self)) {
    console.log("receive message from the parent window:", msg);
}

Example (EventEmitter)

for await (const msg of read(process)) {
    console.log("receive message from the parent process:", msg);
}

jsext.readAll

function readAll<T>(iterable: AsyncIterable<T>): Promise<T[]>;

Reads all values from the iterable object at once.

Example

const file = fs.createReadStream("./package.json");
const chunks = await readAll(file);

jsext.chan

function chan<T>(capacity?: number): Channel<T>;

Inspired by Golang, cerates a Channel that can be used to transfer data across routines.

If capacity is not set, a non-buffered channel will be created. For a non-buffered channel, the sender and receiver must be present at the same time (theoretically), otherwise, the channel will block (non-IO aspect).

If capacity is set, a buffered channel will be created. For a buffered channel, data will be queued in the buffer first and then consumed by the receiver in FIFO order. Once the buffer size reaches the capacity limit, no more data will be sent unless there is new space available.

It is possible to set the capacity to Infinity to allow the channel to never block and behave like a message queue.

Unlike EventEmitter or EventTarget, Channel guarantees the data will always be delivered, even if there is no receiver at the moment.

Also, unlike Golang, await channel.pop() does not prevent the process from exiting.

Channels can be used to send and receive streaming data between main thread and worker threads wrapped by parallel(), but once used that way, channel.close() must be explicitly called in order to release the channel for garbage collection.

Example (non-buffered)

const channel = chan<number>();

(async () => {
    await channel.push(123);
})();

const num = await channel.pop();
console.log(num); // 123

Example (buffered)

const channel = chan<number>(3);

await channel.push(123);
await channel.push(456);
await channel.push(789);

const num1 = await channel.pop();
const num2 = await channel.pop();
const num3 = await channel.pop();

console.log(num1); // 123
console.log(num2); // 456
console.log(num3); // 789

Example (iterable)

const channel = chan<number>();

(async () => {
    for (const num of Number.sequence(1, 5)) {
        await channel.push(num);
    }

    channel.close();
})();

for await (const num of channel) {
    console.log(num);
}
// output:
// 1
// 2
// 3
// 4
// 5

jsext.parallel

function parallel<M extends { [x: string]: any; }>(
    mod: string | (() => Promise<M>)
): ThreadedFunctions<M>;

Wraps a module so its functions are run in worker threads.

In Node.js and Bun, the module can be either an ES module or a CommonJS module, node_modules and built-in modules are also supported.

In browsers and Deno, the module can only be an ES module.

In Bun and Deno, the module can also be a TypeScript file.

Data are cloned and transferred between threads via Structured Clone Algorithm.

Apart from the standard data types supported by the algorithm, Channel can also be used to transfer data between threads. To do so, just passed a channel instance to the threaded function. But be aware, channel can only be used as a parameter, return a channel from the threaded function is not allowed. Once passed, the data can only be transferred into and out-from the function.

The difference between using a channel and a generator function for streaming processing is, for a generator function, next(value) is coupled with a yield value, the process is blocked between next calls, channel doesn't have this limit, we can use it to stream all the data into the function before processing and receiving any result.

The threaded function also supports ArrayBuffers as transferable objects. If an array buffer is presented as an argument or the direct property of an argument (assume it's a plain object), or the array buffer is the return value or the direct property of the return value (assume it's a plain object), it automatically becomes a transferrable object and will be transferred to the other thread instead of being cloned. This strategy allows us to easily compose objects like Request and Response instances into plain objects and pass them between threads without overhead.

NOTE: if the current module is already in a worker thread, use this function won't create another worker thread.

NOTE: cloning and transferring data between the main thread and worker threads are very heavy and slow, worker threads are only intended to run CPU-intensive tasks and prevent blocking the main thread, they have no advantage when performing IO-intensive tasks such as handling HTTP requests, always prefer cluster module for that kind of purpose.

Example (regular or async function)

const mod = parallel(() => import("./examples/worker.mjs"));
console.log(await mod.greet("World")); // Hi, World

Example (generator or async generator function)

const mod = parallel(() => import("./examples/worker.mjs"));

for await (const word of mod.sequence(["foo", "bar"])) {
    console.log(word);
}
// output:
// foo
// bar

Example (use channel)

const mod = parallel(() => import("./examples/worker.mjs"));

const channel = chan<{ value: number; done: boolean; }>();
const length = mod.twoTimesValues(channel);

for (const value of Number.sequence(0, 9)) {
    await channel.push({ value, done: value === 9 });
}

const results = (await readAll(channel)).map(item => item.value);
console.log(results);      // [0, 2, 4, 6, 8, 10, 12, 14, 16, 18]
console.log(await length); // 10

Example (use transferrable)

const mod = parallel(() => import("./examples/worker.mjs"));

const arr = Uint8Array.from([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
const length = await mod.transfer(arr.buffer);

console.log(length);     // 10
console.log(arr.length); // 0

NOTE: if the application is to be bundled, use the following syntax to link the module instead, it will prevent the bundler from including the file and rewriting the path.

const mod = parallel<typeof import("./examples/worker.mjs")>("./examples/worker.mjs");

namespace parallel {
    /**
     * The maximum number of workers allowed to exist at the same time. If not set, the program
     * by default uses CPU core numbers as the limit.
     */
    export var maxWorkers: number | undefined;

    /**
     * In browsers, by default, the program loads the worker entry directly from GitHub,
     * which could be slow due to poor internet connection, we can copy the entry file
     * `bundle/worker.mjs` to a local path of our website and set this option to that path
     * so that it can be loaded locally.
     * 
     * Or, if the code is bundled, the program won't be able to automatically locate the entry
     * file in the file system, in such case, we can also copy the entry file
     * (`bundle/worker.mjs` for Bun, Deno and the browser, `bundle/worker-node.mjs` for Node.js)
     * to a local directory and supply this option instead.
     */
    export var workerEntry: string | undefined;
}

jsext.run

function run<R, A extends any[] = any[]>(script: string, args?: A, options?: {
    /** If not set, invoke the default function, otherwise invoke the specified function. */
    fn?: string;
    /** Automatically abort the task when timeout (in milliseconds). */
    timeout?: number;
    /**
     * Instead of dropping the worker after the task has completed, keep it alive so that it can
     * be reused by other tasks.
     */
    keepAlive?: boolean;
    /**
     * Choose whether to use `worker_threads` or `child_process` for running the script.
     * The default setting is `worker_threads`.
     * 
     * In browsers and Deno, this option is ignored and will always use the web worker.
     * 
     * @deprecated Always prefer `worker_threads` over `child_process` since it consumes
     * less system resources.
     */
    adapter?: "worker_threads" | "child_process";
}): Promise<{
    workerId: number;
    /** Retrieves the return value of the function that has been called. */
    result(): Promise<R>;
    /** Iterates the yield value if the function returns a generator. */
    iterate(): AsyncIterable<R>;
    /** Terminates the worker thread and aborts the task. */
    abort(reason?: unknown): Promise<void>;
}>;

Runs the given script in a worker thread or child process.

In Node.js and Bun, the script can be either an ES module or a CommonJS module, and is relative to the current working directory if not absolute.

In browsers and Deno, the script can only be an ES module, and is relative to the current URL (or working directory in Deno) if not absolute.

In Bun and Deno, the script can also be a TypeScript file.

This function also uses parallel.maxWorkers and parallel.workerEntry for worker configuration by default. Channel can also be used to transfer streaming data into the function being called. ArrayBuffers are also supported as transferrable objects if they are presented as arguments or the return value (or their direct properties).

Example (result)

const job1 = await run<string, [string]>("examples/worker.mjs", ["World"]);
console.log(await job1.result()); // Hello, World

Example (iterate)

const job2 = await run<string, [string[]]>("examples/worker.mjs", [["foo", "bar"]], {
    fn: "sequence",
});
for await (const word of job2.iterate()) {
    console.log(word);
}
// output:
// foo
// bar

Example (abort)

const job3 = await run<string, [string]>("examples/worker.mjs", ["foobar"], {
    fn: "takeTooLong",
});
await job3.abort();
const [err, res] = await _try(job3.result());
console.assert(err === null);
console.assert(res === undefined);

namespace run {
    /**
     * The maximum number of workers allowed to exist at the same time. If not set, use the same
     * setting as {@link parallel.maxWorkers}.
     */
    var maxWorkers: number | undefined;
}

jsext.example

function example<T, A extends any[] = any[]>(
    fn: (this: T, console: Console, ...args: A) => void | Promise<void>,
    options?: {
        /** Suppress logging to the terminal and only check the output. */
        suppress?: boolean;
    }
): (this: T, ...args: A) => Promise<void>;

Inspired by Golang's Example as Test design, creates a function that carries example code with // output: comments, when the returned function is called, it will automatically check if the actual output matches the one declared in the comment.

The example function receives a customized console object which will be used to log outputs instead of using the built-in console.

NOTE: this function is used to simplify the process of writing tests, it does not work in Bun and browsers currently, because Bun hasn't implement the Console constructor and removes comments during runtime, and the function relies on Node.js built-in modules.

Example

it("should output as expected", example(console => {
    console.log("Hello, World!");
    // output:
    // Hello, World!
}));

jsext.deprecate

function deprecate<T, Fn extends (this: T, ...args: any[]) => any>(
    fn: Fn,
    tip?: string,
    once?: boolean
): Fn;

Marks a function as deprecated and returns a wrapped function.

When the wrapped function is called, a deprecation warning will be emitted to the stdout.

NOTE: the original function must have a name.

Example

const sum = deprecate(function sum(a: number, b: number) {
    return a + b;
}, "use `a + b` instead");
console.log(sum(1, 2));
// output:
// DeprecationWarning: sum() is deprecated, use `a + b` instead (at <anonymous>:4:13)
// 3

function deprecate(target: string, forFn: Function, tip?: string, once?: boolean): void;

Emits a deprecation warning for the target, usually a parameter, an option, or the function's name, etc.

Example

const pow = function pow(a: number, b: number) {
    deprecate("pow()", pow, "use `a ** b` instead");
    return a ** b;
};
console.log(pow(2, 3));
// output:
// DeprecationWarning: pow() is deprecated, use `a ** b` instead (at <anonymous>:5:13)
// 8

Types

• Channel<T>
• Queue<T>
• AsyncFunction
• AsyncGeneratorFunction
• AsyncFunctionConstructor
• Constructor<T>
• TypedArray
• Optional<T, K extends keyof T>
• Ensured<T, K extends keyof T>

When augmenting, these types are exposed to the global scope (except for Channel and Queue).

Sub-packages

• string Functions for dealing with strings.
• number Functions for dealing with numbers.
• array Functions for dealing with arrays.
• uint8array Functions for dealing with Uint8Arrays.
• object Functions for dealing with objects.
• json Functions for parsing JSONs to specific structures.
• math Functions for the mathematical calculations.
• promise Functions for promise/async context handling.
• error Functions for transferring errors to/from other types of objects.
• collections Additional collection data types.

NOTE: Configure tsconfig.json to set compilerOptions.module as NodeNext or ESNext instead of CommonJS in order to use sub-packages.

NOTE: The following examples of module specifiers uses Node.js style, but they have Deno and browser equivalents, like this:

• Node.js @ayonli/jsext/string
• Deno: https://lib.deno.dev/x/ayonli_jsext@latest/string/index.ts
• Browser: https://lib.deno.dev/x/ayonli_jsext@latest/esm/string/index.js

string

import { compare, random, /* ... */ } from "@ayonli/jsext/string";
// or
import "@ayonli/jsext/string/augment";

Functions

• compare(str1: string, str2: string): -1 | 0 | 1
• random(length: number): string
• count(str: string, sub: string): number
• capitalize(str: string, all?: boolean): string
• hyphenate(str: string): string
• words(str: string): string[]
• chunk(str: string, length: number): string[]
• truncate(str: string, length: number): string
• trim(str: string, chars?: string): string
• trimEnd(str: string, chars?: string): string
• trimStart(str: string, chars?: string): string
• byteLength(str: string): number

Augmentation

• String
  • compare(str1: string, str2: string): -1 | 0 | 1
  • random(length: number): string
  • prototype
    • count(sub: string): number
    • capitalize(all?: boolean): string
    • hyphenate(): string
    • words(): string[]
    • chunk(length: number): string[]
    • truncate(length: number): string
    • trim(chars?: string): string
    • trimEnd(chars?: string): string
    • trimStart(chars?: string): string
    • byteLength(): number

number

import { isFloat, isNumeric, /* ... */ } from "@ayonli/jsext/number";
// or
import "@ayonli/jsext/number/augment";

Functions

• isFloat(value: unknown): boolean
• isNumeric(value: unknown): boolean
• isBetween(value: number, [min, max]: [number, number]): boolean
• random(min: number, max: number): number
• sequence(min: number, max: number, step?: number, loop?: boolean): Generator<number, void, unknown>

When augmenting, these functions are attached to the Number constructor.

array

import { count, equals, /* ... */ } from "@ayonli/jsext/array";
// or
import "@ayonli/jsext/array/augment";

Functions

• count<T>(arr: RealArrayLike<T>, ele: T): number
• equals<T>(arr1: RealArrayLike<T>, arr2: RealArrayLike<T>): boolean
• split<T>(arr: RealArrayLike<T>, delimiter: T): RealArrayLike<T>[]
• chunk<T>(arr: RealArrayLike<T>, length: number): RealArrayLike<T>[]
• uniq<T>(arr: T[]): T[]
• shuffle<T>(arr: T[]): T[]
• orderBy<T>(arr: T[], key: keyof T, order: "asc" | "desc" = "asc"): T[]
• groupBy<T>(arr: T[], fn: (item: T, i: number) => string | symbol, type?: ObjectConstructor): Record<string | symbol, T[]>
• groupBy<T, K extends string>(arr: T[], fn: (item: T, i: number) => K, type: MapConstructor): Map<K, T[]>

Augmentation

• Array<T>
  • prototype
    • first(): T
    • last(): T
    • count(ele: T): number
    • equals(another: T[]): boolean
    • split(delimiter: T): T[][]
    • chunk(length: number): T[][]
    • uniq(): T[]
    • shuffle(): T[]
    • toShuffled(): T[]
    • toReversed(): T[]
    • toSorted(fn?: ((a: T, b: T) => number) | undefined): T[]
    • orderBy(key: keyof T, order?: "asc" | "desc"): T[]
    • groupBy(fn: (item: T, i: number) => string | symbol, type?: ObjectConstructor): Record<string | symbol, T[]>
    • groupBy<K>(fn: (item: T, i: number) => K, type: MapConstructor): Map<K, T[]>

uint8array

import { compare, equals, /* ... */ } from "@ayonli/jsext/uint8array";
// or
import "@ayonli/jsext/uint8array/augment";

Functions

• copy(src: Uint8Array, dest: Uint8Array): number
• concat<T extends Uint8Array>(...arrays: T[]): T
• compare(arr1: Uint8Array, arr2: Uint8Array): -1 | 0 | 1
• equals(arr1: Uint8Array, arr2: Uint8Array): boolean
• split<T extends Uint8Array>(arr: T, delimiter: number): T[]
• chunk<T extends Uint8Array>(arr: T, length: number): T[]

Augmentation

• Uint8Array
  • copy(src: Uint8Array, dest: Uint8Array): number
  • concat<T extends Uint8Array>(...arrays: T[]): T
  • compare(arr1: Uint8Array, arr2: Uint8Array): -1 | 0 | 1
  • prototype
    • equals(another: Uint8Array): boolean
    • split(delimiter: number): this[]
    • chunk(length: number): this[]

object

import { hasOwn, hasOwnMethod, /* ... */ } from "@ayonli/jsext/object";
// or
import "@ayonli/jsext/object/augment";

Functions

• hasOwn(obj: any, key: string | number | symbol): boolean
• hasOwnMethod(obj: any, method: string | symbol): boolean
• patch<T extends {}, U>(target: T, source: U): T & U
• patch<T extends {}, U, V>(target: T, source1: U, source2: V): T & U & V
• patch<T extends {}, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W
• patch(target: object, ...sources: any[]): any
• pick<T extends object, U extends keyof T>(obj: T, keys: U[]): Pick<T, U>
• pick<T>(obj: T, keys: (string | symbol)[]): Partial<T>
• omit<T extends object, U extends keyof T>(obj: T, keys: U[]): Omit<T, U>
• omit<T>(obj: T, keys: (string | symbol)[]): Partial<T>
• as(value: unknown, type: StringConstructor): string | null
• as(value: unknown, type: NumberConstructor): number | null
• as(value: unknown, type: BigIntConstructor): bigint | null
• as(value: unknown, type: BooleanConstructor): boolean | null
• as(value: unknown, type: SymbolConstructor): symbol | null
• as<T>(value: unknown, type: Constructor<T>): T | null
• isValid(value: unknown): boolean
• isPlainObject(value: unknown): value is { [x: string | symbol]: any; }

When augmenting, these functions are attached to the Object constructor.

json

import { parseAs } from "@ayonli/jsext/json";
// or
import "@ayonli/jsext/json/augment";

Functions

• parseAs(text: string, type: StringConstructor): string | null
• parseAs(text: string, type: NumberConstructor): number | null
• parseAs(text: string, type: BigIntConstructor): bigint | null
• parseAs(text: string, type: BooleanConstructor): boolean | null
• parseAs<T>(text: string, type: Constructor<T> & { fromJSON?(data: any): T; }): T | null
• as(data: unknown, type: StringConstructor): string | null
• as(data: unknown, type: NumberConstructor): number | null
• as(data: unknown, type: BigIntConstructor): bigint | null
• as(data: unknown, type: BooleanConstructor): boolean | null
• as<T>(data: unknown, type: Constructor<T> & { fromJSON?(data: any): T; }): T | null
• type(ctor: Constructor<any>): PropertyDecorator

When augmenting, these functions are attached to the JSON namespace.

math

import { sum, avg, /* ... */ } from "@ayonli/jsext/math";
// or
import "@ayonli/jsext/math/augment";

Functions

• sum(...values: number[]): number
• avg(...values: number[]): number
• product(...values: number[]): number

When augmenting, these functions are attached to the Math namespace.

promise

import { timeout, after, /* ... */ } from "@ayonli/jsext/promise";
// or
import "@ayonli/jsext/promise/augment";

Functions

• timeout<T>(value: T | PromiseLike<T>, ms: number): Promise<T>
• after<T>(value: T | PromiseLike<T>, ms: number): Promise<T>
• sleep(ms: number): Promise<void>
• until(test: () => boolean | Promise<boolean>): Promise<void>

When augmenting, these functions are attached to the Promise constructor.

error

import Exception from "@ayonli/jsext/error/Exception";
// or
import { Exception, toObject, /* ... */ } from "@ayonli/jsext/error";
// or
import "@ayonli/jsext/error/augment";

Types

• Exception (extends Error)
  • cause?: unknown
  • code: number

When augmenting, these types are exposed to the global scope.

Functions

• toObject<T extends Error>(err: T): { [x: string | symbol]: any; }
• fromObject<T extends Error>(obj: { [x: string | symbol]: any; }, ctor?: Constructor<T>): T
• toErrorEvent(err: Error, type?: string): ErrorEvent
• fromErrorEvent<T extends Error>(event: ErrorEvent): T | null

Augmentation

• Error
  • toObject<T extends Error>(err: T): { [x: string | symbol]: any; }
  • fromObject<T extends Error>(obj: { [x: string | symbol]: any; }, ctor?: Constructor<T>): T
  • toErrorEvent(err: Error, type?: string): ErrorEvent
  • fromErrorEvent<T extends Error>(event: ErrorEvent): T | null
  • prototype
    • toJSON(): { [x: string | symbol]: any; }

collections

import BiMap from "@ayonli/jsext/collections/BiMap";
import CiMap from "@ayonli/jsext/collections/CiMap";
// or
import { BiMap, CiMap } from "@ayonli/jsext/collections";
// or
import "@ayonli/jsext/collections/augment";

Types

• BiMap<K, V> (extends Map<K, V>) Bi-directional map, keys and values are unique and map to each other.
  • prototype (additional)
    • getKey(value: V): K | undefined
    • hasValue(value: V): boolean
    • deleteValue(value: V): boolean
• CiMap<K extends string, V> (implements Map<K, V>) Case-insensitive map, keys are case-insensitive.

When augmenting, these types are exposed to the global scope.

Import all sub-package augmentations at once

import "@ayonli/jsext/augment";

When to use augmentations

If we're developing libraries and share them publicly, in order to prevent collision, it's better not to use augmentations, but use the corresponding functions from the sub-packages instead.

But if we're developing private application, using augmentations can save a lot of time, it's easier to read and write, and make sense.