lahmatiy

// react 0.14-rc1
var Zoo = React.createClass({
  render: function() {
    return <div>Giraffe name: <input ref="giraffe" /></div>;
  },
  showName: function() {
    // Previously: var input = this.refs.giraffe.getDOMNode();
    var input = this.refs.giraffe;
    alert(input.value);
  }

lahmatiy

var csso = require('csso');

function splitByScope(css) {
    var scopes = {};

    csso.walk(csso.parse(css), function(node) {
        if (node.type === 'Class') {
            var className = node.name;
            var scopeId = className.replace(/^([^_]+)_.+/, '$1'); // scopeId is block name

lahmatiy

var events = require('basis.event');
var resolveValue = require('basis.data').resolveValue;

module.exports = function createBlockClass(BaseClass, ext) {
    return BaseClass.subclass(ext, {
        visible: true,
        visibleRA_: null,
        emit_visibleChanged: events.create('visibleChanged'),
        // value could be a function or binding-bridge instance; any other converts to bool
        setVisible: function(value) {

lahmatiy

// Unique with use object
function uniqueObject(array) {
    var hash = Object.create(null);
    var result = [];
    var value;

    for (var i = 0; i < array.length; i++) {
        value = array[i];
        if (!hash[value]) {
            hash[value] = true;

lahmatiy

//
// Case 1
//

var a = [];
var t = performance.now();

for (var i = 0; i < 10000; i++)
  a.push(new Promise(function(){}));
  

lahmatiy

Similar solutions with very different execution times. What's the reason? Why solution #1 is too slow?

Hint: access to .length property and to variables is not an issue.

Based on a real case in CSSTree

Node v6.11.3

N	Solution #1	Solution #2

lahmatiy

const csstree = require('css-tree');
const data = require('mdn-data/css/properties.json');

Object.keys(data).forEach(name => {
    const prop = data[name];

    if (Array.isArray(prop.initial)) {
        return;
    }

lahmatiy

const csstree = require('css-tree');

const ast1 = csstree.parse('.a { color: red }', {
  filename: './a.css',
  positions: true
});
const ast2 = csstree.parse('.b { color: red }', {
  filename: './b.css',
  positions: true
});

lahmatiy

const pngSignature = Buffer.from([137, 80, 78, 71, 13, 10, 26, 10]);
const hashKey = 'react-snapshot-hash';
const crcTable = [];
const initialCrc = 0xffffffff;

for (let n = 0; n < 256; n++) {
    let c = n;

    for (let k = 0; k < 8; k++) {
        if (c & 1) {

lahmatiy

// UPDATE: you can use ready to use package prop-types-definition
// https://github.com/avito-tech/prop-types-definition

module.exports = function(content) {
    return content + `
(function(ReactPropTypes) {
  function unwrapValueItem(value) {
    if (value) {
      if (typeof value.getTypeDefinition === 'function') {
        return value.getTypeDefinition();