bvaughn

This API was removed in React 17

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Interaction tracing with React

React recently introduced an experimental profiler API. After discussing this API with several teams at Facebook, one common piece of feedback was that the performance information would be more useful if it could be associated with the events that caused the application to render (e.g. button click, XHR response). Tracing these events (or "interactions") would enable more powerful tooling to be built around the timing information, capable of answering questions like "What caused this really slow commit?" or "How long does it typically take for this interaction to update the DOM?".

With version 16.4.3, React added experimental support for this tracing by way of a new NPM package, scheduler. However the public API for this package is not yet finalized and will likely change with upcoming minor releases, so it should be used with caution.

bvaughn

const createLogger = (backgroundColor, color) => {
  const logger = (message, ...args) => {
    if (logger.enabled === false) {
      return;
    }

    console.groupCollapsed(
      `%c${message}`,
      `background-color: ${backgroundColor}; color: ${color}; padding: 2px 4px;`,
      ...args

swalkinshaw

Moved to Shopify/graphql-design-tutorial

pcattori

import { Base64 } from 'js-base64'
import { Op } from 'sequelize'
import { fromGlobalId } from 'graphql-relay'

// https://github.com/graphql/graphql-relay-js/issues/94#issuecomment-232410564

const effectiveOrder = ({ last }, orderBy) => {
    /* adds `id ASC` to end of `ORDER BY` if `id` is not already in the `ORDER BY` clause
    flips `ASC` to `DESC` (and vice-versa) if pagination arg `last` is defined
    */

mattmazzola

var graphql = require('graphql');

export function Edge(itemType: any) {
    return new graphql.GraphQLObjectType({
        name: "Edge",
        description: "Generic edge to allow cursors",
        fields: () => ({
            node: { type: itemType },
            cursor: { type: graphql.GraphQLString }
        })

gaearon

A top-level App component returns <Button /> from its render() method.

1. What is the relationship between <Button /> and this in that Button’s render()?

2. Does rendering <Button><Icon /></Button> guarantee that an Icon mounts?

3. Can the App change anything in the Button output? What and how?

---

kejun

var React         = require('react');
var EventListener = require('react/lib/EventListener');
var partition     = require('linear-partitioning');

var TileLayout = React.createClass({
  getDefaultProps: function() {
    return {
      gutter: 0,
      photos: []
    }

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD