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JS Pop Quiz: How well do you know your functions?

Given an Array of Functions fns, what argument(s) can you pass to fns.forEach such that each function in fns will execute, in order, without creating any anonymous (or named) functions or invoking the Function constructor?

Conditions

• Do not use the function keyword, or arrow functions () => .
• Do not invoke the Function constructor.
• Do not use method definitions.
• Function#bind & friends on the Function.prototype are ok.

timoxley

const date = require('date.js')
google.charts.load('current', {packages: ['corechart', 'line']});
google.charts.setOnLoadCallback(() => {
  fetch('https://crossorigin.me/https://wakatime.com/leaders', {mode: 'cors', credentials: 'same-origin'})
  .then(res => (console.log('res', res), res))
  .then(res => res.text())
  .then(html => {
    const frag = document.createDocumentFragment()
    const div = frag.appendChild(document.createElement('div'))
    div.innerHTML = html

timoxley

function (toMatch, items) {
  const options = arguments[arguments.length - 1] // options always last arg
  if (!Array.isArray(items)) items = [] // items is optional
  if (!toMatch) throw new Error('No value given to match')
  if (!options || Array.isArray(options)) throw new Error('No internal options object')
}

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// cat.js
// cat a.js b.js | node cat.js

var vm = require('vm')
var a = ''
process.stdin.on('data', function(b) {
  a += b.toString()
})
process.stdin.on('end', function() {
  vm.runInThisContext(a)

timoxley

Organizing Programs Without Classes

Source: https://cs.au.dk/~hosc/local/LaSC-4-3-pp223-242.pdf

Section 2.5 Dynamic Behavior Changes: Changing An Instance’s Class and Dynamic Inheritance

tl;dr

Sometimes the behavior of an instance of a data type can be divided into several different “modes” of behavior or implementation…

timoxley

var columnify = require('columnify')
var fs = require('fs')
var results = [];
var packages = JSON.parse(fs.readFileSync(process.env.HOME + '/.npm/registry.npmjs.org/-/all/.cache.json'))
var packageNames = Object.keys(packages)

// only count packages with dist-tags + latest
var validPackages = packageNames.filter(function(name) {
  var item = packages[name];
  return (

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Test

This is a test

Examples

An example:

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  // paste into console on http://www.polymer-project.org/ and inspect document body
  // template appears, but not rendered data
  
  var doc = document.implementation.createHTMLDocument()
  doc.body.innerHTML = [
    '<template repeat="{{key, value in items}}">',
    '  {{key}} {{value}}',
    '</template>'
  ].join('\n')
  

timoxley

var NUM_BUCKETS = 5
var data = [100, 200, 120, 130, 150]
var max = data.reduce(function(max, num) {return Math.max(max, num)}, -Infinity)
var min = data.reduce(function(min, num) {return Math.min(min, num)}, Infinity)
var interval = (max - min) / NUM_BUCKETS
var toBucket = function toBucket(num) {
  var bucket = Math.floor((num - min) / interval)
  // constrain to 0 -> NUM_BUCKETS - 1
  return Math.max(0, Math.min(bucket, NUM_BUCKETS - 1))
}

timoxley

@@ -1,6 +1,6 @@
 @media not print {
     .screen-scroll,.screen-scroll>body,.screen-scroll .container {
-        overflow: hidden
+        height: 100%;
     }
 
     .screen-scroll .surface {
@@ -9,7 +9,6 @@