ericelliott

class User {
  constructor ({ name = 'Anonymous' }) {
    this.name = name;
  }
  login () {
    console.log(`${ this.name } logged in.`);
  }
};

class Student extends User {

ericelliott

const filter = (fn, arr) => arr.reduce((newArr, item) => {
  return fn(item) ? newArr.concat([item]) : newArr;
}, []);

ericelliott

const curry = fn => (...args1) => {
  if (args1.length === fn.length) {
    return fn(...args1);
  }

  return (...args2) => {
    const args = [...args1, ...args2];

    if (args.length >= fn.length) {
      return fn(...args);

ericelliott

import speculation from 'speculation';

const wait = (
  time,
  cancel = Promise.reject() // By default, don't cancel
) => speculation((resolve, reject, onCancel) => {
  const timer = setTimeout(resolve, time);

  // Use onCancel to clean up any lingering resources
  // and then call reject(). You can pass a custom reason.

ericelliott

// HOF Wraps the native Promise API
// to add take a shouldCancel promise and add
// an onCancel() callback.
const speculation = (
  fn,
  cancel = Promise.reject() // Don't cancel by default
) => new Promise((resolve, reject) => {
  const noop = () => {};

  const onCancel = (

ericelliott

const wait = time => new Promise(
  res => setTimeout(() => res(), time)
);

wait(200)
  // onFulfilled() can return a new promise, `x`
  .then(() => new Promise(res => res('foo')))
  // the next promise will assume the state of `x`
  .then(a => a)
  // Above we returned the unwrapped value of `x`

ericelliott

const wait = (
  time,
  cancel = Promise.reject()
) => new Promise((resolve, reject) => {
  const timer = setTimeout(resolve, time);
  const noop = () => {};

  cancel.then(() => {
    clearTimeout(timer);
    reject(new Error('Cancelled'));

ericelliott

const wait = time => new Promise((resolve) => setTimeout(resolve, time));

wait(3000).then(() => console.log('Hello!')); // 'Hello!'

ericelliott

const double = n => n.points * 2;

const doubleMap = numbers => numbers.map(double);

console.log(doubleMap([
  { name: 'ball', points: 2 },
  { name: 'coin', points: 3 },
  { name: 'candy', points: 4}
])); // [ 4, 6, 8 ]

ericelliott

const double = n => n * 2;
const doubleMap = numbers => numbers.map(double);
console.log(doubleMap([2, 3, 4])); // [ 4, 6, 8 ]