utils

@yuuza/utils

Classes

Callbacks

Events in JS/TS with easy typing/autocompletion.

Example:

class MusicPlayer {
  onPlay = new Callbacks<() => void>();
  // ...
  play() {
    // ...
    // Call/invoke the callbacks:
    this.onPlay.invoke();
  }
}

const player = new MusicPlayer();
// ...
player.onPlay.add(() => {
  console.info("player play");
});

Ref

Ref with onChanged callbacks.

Example:

class MusicPlayer {
  refState = new Ref<"stopped" | "playing" | "paused">("stopped");
  // ...
  play() {
    // ...
    this.refState.value = "playing";
  }
}

const player = new MusicPlayer();
// ...
player.refState.onChanged.add(() => {
  console.info("player current state:", player.refState.value);
});

Semaphore

Example:

// Limit the concurrency of downloads
const downloadLimit = new Semaphore({ maxCount: 5 });
async function download() {
  // Will block/await here if >= 5 downloads currently running,
  await downloadLimit.enter();
  try {
    await actuallyDownload();
  } finally {
    downloadLimit.exit();
  }
}

Or shorter version with run():

const downloadLimit = new Semaphore({ maxCount: 5 });
function download() {
  return downloadLimit.run(async () => {
    await actuallyDownload();
  });
}

Lazy

CancelToken

AutoResetEvent

EventRegistrations

Functions

(TBD)

strPadLeft

function strPadLeft(str: string, len: number, ch?: string): string;

formatDuration

function formatDuration(sec: number | any): string;

formatFileSize

function formatFileSize(size: number | any): string;

formatDateTime

function formatDateTime(date: Date): string;

numLimit

function numLimit(num: number, min: number, max: number): number;

createName

function createName(
  nameFunc: (num: number) => string,
  existsFunc: (str: string) => boolean
): string;

base64EncodeUtf8

function base64EncodeUtf8(str: any): string;

sleepAsync

function sleepAsync(time: number): Promise<void>;

arrayRemove

function arrayRemove<T>(array: T[], val: T): void;

arrayInsert

function arrayInsert<T>(array: T[], val: T, pos?: number): void;

arrayMap

function arrayMap<T, TRet>(
  arr: Iterable<T>,
  func: (item: T, idx: number) => TRet
): TRet[];

arrayForeach

function arrayForeach<T>(
  arr: Iterable<T>,
  func: (item: T, idx: number) => void
): void;

foreachFlaten

function foreachFlaten<T>(arr: T[], func: Action<T>): void;

arrayFind

function arrayFind<T>(
  arr: Iterable<T>,
  func: (item: T, idx: number) => any
): T | null;

arraySum

function arraySum<T>(
  arr: Iterable<T>,
  func: (item: T) => number | null | undefined
): number;

objectApply

function objectApply<T>(
  obj: Partial<T>,
  kv?: Partial<T>,
  keys?: Array<keyof T>
): Partial<T>;

objectInit

function objectInit<T>(obj: T, kv?: ObjectInit<T>, keys?: Array<keyof T>): T;

mod

function mod(a: number, b: number): number;

readBlobAsDataUrl

function readBlobAsDataUrl(blob: Blob): Promise<string>;