JamieMason

// Generally Expected Flow (actions and implementation are missing)
//
// 1 renderNode runs logic which inspects this hard-coded rootNode
// 2 transtions to renderBranch because it has children
// 3 there are two children so the UI would display them
// 4 user chooses the first child
// 5 fetchNode finds no children property, so there is nothing more to load
// 6 fetchNode resolves success with the node
// 7 renderNode runs logic which inspects the node
// 8 transtions to renderLeaf because it has no children

JamieMason

export default function transformer(file, api) {
  const j = api.jscodeshift;

  const toPascalCase = str =>
    `${str}`
      .replace(new RegExp(/[-_]+/, 'g'), ' ')
      .replace(new RegExp(/[^\w\s]/, 'g'), '')
      .replace(
        new RegExp(/\s+(.)(\w+)/, 'g'),
        ($1, $2, $3) => `${$2.toUpperCase() + $3.toLowerCase()}`

JamieMason

Pluck Unique Values from Array of Javascript Objects

Implementation

const pluck = key => array => Array.from(new Set(array.map(obj => obj[key])));

Usage

JamieMason

Group Array of JavaScript Objects by Key or Property Value

Implementation

const groupBy = key => array =>
  array.reduce((objectsByKeyValue, obj) => {
    const value = obj[key];
    objectsByKeyValue[value] = (objectsByKeyValue[value] || []).concat(obj);
    return objectsByKeyValue;

JamieMason

Learning about JavaScript Transducers

Work in progress sketch based on following along with the video course at https://egghead.io/courses/quickly-transform-data-with-transducers.

Source

const id = (value) => value;
const isArray = (value) => Array.isArray(value);
const isNumber = (value) => typeof value === 'number';

JamieMason

List all assignees of a GitHub Milestone

1. Visit the milestone at eg. https://github.com/USER/REPO/milestone/1
2. Run this in your console

   [...document.querySelectorAll('.from-avatar')].map(el => el.getAttribute('alt'))

3. An array of GitHub usernames will be logged.

JamieMason

List all peerDependencies for packages in a Lerna Monorepo

System Requirements

brew install jq
npm install -g glob-exec

Usage

JamieMason

const childProcess = require('child_process');
const fs = require('fs');
const path = require('path');
const glob = require('glob');

const filePaths = glob
  .sync('package.json')
  .concat(glob.sync('packages/*/package.json'))
  .map(filePath => path.resolve(process.cwd(), filePath));

JamieMason

const exec = require('child_process').exec;

const sortBy = (key, reverse) => {
  const moveSmaller = reverse ? 1 : -1;
  const moveLarger = reverse ? -1 : 1;
  return (a, b) => {
    if (a[key] < b[key]) {
      return moveSmaller;
    }
    if (a[key] > b[key]) {

JamieMason

function Maybe(x) {
  if (this instanceof Maybe === false) {
    return new Maybe(x);
  }
  this.value = x;
}

Maybe.prototype.map = fn => (this.value == null ? this : new Maybe(fn(this.value)));

function Either(left, right) {