bvaughn

React recently introduced an experimental profiler API. This page gives instructions on how to use this API in a production release of your app.

Table of Contents

• Profiling in production
  • Create React App
  • Webpack 4

Profiling in production

React DOM automatically supports profiling in development mode for v16.5+, but since profiling adds some small additional overhead it is opt-in for production mode. This gist explains how to opt-in.

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.

wcandillon

import React from "react";
import {
  StyleSheet,
  Text,
  View,
  ScrollView,
  Animated,
  SafeAreaView,
  Dimensions
} from "react-native";

bvaughn

Profiler

React 16.4 will introduce a new Profiler component (initially exported as React.unstable_Profiler) for collecting render timing information in order to measure the "cost" of rendering for both sync and async modes.

Profiler timing metrics are significantly faster than those built around the User Timing API, and as such we plan to provide a production+profiling bundle in the future. (The initial release will only log timing information in DEV mode, although the component will still render its children- without timings- in production mode.)

How is it used?

Profiler can be declared anywhere within a React tree to measure the cost of rendering that portion of the tree. For example, a Navigation component and its descendants:

gtkatakura

type ThemeColor = string;
type Theme = { id: number, color: ThemeColor }
type State = { themes?: [Theme] }

interface CurriedFunction1<T1, R> {
    (t1: T1): R;
}

interface CurriedFunction2<T1, T2, R> {
    (t1: T1): CurriedFunction1<T2, R>;

vcarl

I bundled these up into groups and wrote some thoughts about why I ask them!

If these helped you, I'd love to hear about it!! I'm on twitter @vcarl_ or send me an email carl.vitullo@gmail.com

Onboarding and the workplace

https://blog.vcarl.com/interview-questions-onboarding-workplace/

• How long will it take to deploy my first change? To become productive? To understand the codebase?
• What kind of equipment will I be provided? Will the company pay/reimburse me if I want something specific?

levelsio

<?php

/*
 I wrote this function to progressively obfuscate text in MAKEbook.io. When it KINDA worked, I just used it.
 It can take a lot of improvement. I kinda just tweaked the values until it was good enough. It's not SO progressive though.
 
 It takes all the output of your PHP scripts via ob_start(), reroutes that to the obfuscation function.
 
 You should check if user paid for book or not, then either run ob_start or not!
 

poteto

class FBGroupMemberRemover {
  constructor() {
    this.adminText = 'Admin';
    this.removeMemberModalHeadingText = 'Remove Member';

    this.memberElementSelector = '[data-name="GroupProfileGridItem"]';
    this.memberContextMenuSelector = 'button[aria-label="Member Settings"]';
    this.removeMemberButtonSelector = 'a[data-testid="leave_group"]'

    this.removalOptions = {

adamkl

const { introspectSchema } = require("apollo-codegen");
const { executeWithOptions } = require("graphql-code-generator/dist/cli");
const fs = require("fs");
const path = require("path");

const graphqlPath = "./src/graphql/";
const schemaInput = "./src/graphql/temp.graphql";
const jsonOutput = "./src/graphql/temp.json";
const dtsOutput = "./src/graphql/domain.d.ts";

necolas

import createHoverMonitor from './createHoverMonitor';
import { element, func, oneOfType } from 'prop-types';
import React, { Component } from 'react';

const hover = createHoverMonitor();

/**
 * Use:
 * <Hoverable>
 *   {(hover) => <View style={hover && styles.hovered} />}