ccnokes

// find if number is even or odd
const isEven = val => val % 2 === 0;
isEven(11); //false
isEven(22); //true

// do time related things...
const formatMovieTime = val => {
  const hours = Math.floor(val / 60); //get the hours, discard any remainder via `floor`
  const mins = val % 60; //get the remainder of minutes left over as an integer
  return `${hours}:${mins < 10 ? '0' + mins : mins}`;

ccnokes

{
  "name": "my-ts-lib",
  "version": "1.0.0",
  "description": "My npm package written in TS",
  "main": "dist/index.js",
  "types": "dist/index.d.ts",
  "scripts": {
    "build": "tsc"
  },
  "author": "Cameron Nokes",

ccnokes

// class version
class Queue {
  private p: Promise<any> = Promise.resolve();

  push<T = any>(fn: () => Promise<any>): Promise<T> {
    this.p = this.p
      .then(() => fn())
      .catch(err => {
        console.error(err);
        return fn(); //keep going to next queued

ccnokes

class Deferred<T = any> {
  resolve: (value?: T | PromiseLike<T>) => void;
  reject: (reason?: any) => void;

  promise = new Promise<T>((resolve, reject) => {
    this.resolve = resolve;
    this.reject = reject;
  });

  then = this.promise.then.bind(this.promise);

ccnokes

mkfifo fifo

# produce data and send into fifo
# have to background it because it blocks until the fifo drains/completes
ls -l > fifo &
cat fifo # this drains it and completes the job

ccnokes

import * as _ from 'lodash';

let n = 2;
let someString;

// NOTE `_.pickBy(params, _.negate(_.isNil))` removes undefined/null entries
// so you don't have to worry about `undefined` getting coerced to a string
const formatUrl = (urlStr, params) => urlStr + '?' + 
      new URLSearchParams(_.pickBy(params, _.negate(_.isNil))).toString();

ccnokes

// see working demo here: https://jsfiddle.net/ccnokes/jhu635r8/73/

async function runTasks(taskFns /* Array<() => Promise<any>> */, concurrency = 3) {
  let results = [];
  taskFns = new Set(taskFns);
  let pending = new Set();
  for (let task of taskFns) {
    if (pending.size >= concurrency) {
      await Promise.race(pending);
    }

ccnokes

// see demo: https://jsfiddle.net/ccnokes/6hb92mde/
class Deferred {
  constructor() {
    this.promise = new Promise((resolve, reject) => {
      this.resolve = resolve;
      this.reject = reject;
    });
    this.then = this.promise.then.bind(this.promise);
    this.catch = this.promise.catch.bind(this.promise);
  }

ccnokes

//wrap a fn that returns a function into a decorator
function makeFnWrapDecorator(fnWrapper: Function) {
  return function decoratorWrapper(...args) {
    return function decorator(target, propertyKey: string, descriptor: PropertyDescriptor) {
      const fn = descriptor.value;
      let wrappedFn = fnWrapper.apply(null, [fn, ...args]);
      return {
        configurable: true,
        get() {
          return wrappedFn;

ccnokes

// See demo here: https://jsfiddle.net/ccnokes/xfu3yzce/

/* fake request for remote data */
function request(offset = 0) {
  return new Promise((res) => {
    let data = new Array(5).fill(offset).map((n, i) => n + i);
    setTimeout(() => res({ total: 20, data }), 1000);
  });
}