Bruno Sato brunoksato

This API was removed in React 17

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.

The Rules of React

All libraries have subtle rules that you have to follow for them to work well. Often these are implied and undocumented rules that you have to learn as you go. This is an attempt to document the rules of React renders. Ideally a type system could enforce it.

What Functions Are "Pure"?

A number of methods in React are assumed to be "pure".

On classes that's the constructor, getDerivedStateFromProps, shouldComponentUpdate and render.

	#include <time.h> // Robert Nystrom
	#include <stdio.h> // @munificentbob
	#include <stdlib.h> // for Ginny
	#define r return // 2008-2019
	#define l(a, b, c, d) for (i y=a;y\
	<b; y++) for (int x = c; x < d; x++)
	typedef int i;const i H=40;const i W
	=80;i m[40][80];i g(i x){r rand()%x;
	}void cave(i s){i w=g(10)+5;i h=g(6)
	+3;i t=g(W-w-2)+1;i u=g(H-h-2)+1;l(u

	import { generatePath } from 'react-router-dom';
	import { stringify } from 'query-string';

	const routeTo = (path: string, params: object, qs: object) => {
	const url = generatePath(path, params);

	return qs ? `${url}?${stringify(qs}` : url;
	}

	history.push(routeTo('admin/view/:id', { id: 'ok'}, { anotherParam: 'value' }));

	import React from 'react'
	import { Button, Text, View } from 'react-native'
	import { useDispatch } from 'react-redux'

	import { useReduxState } from '../hooks/use-redux-state'
	import * as actions from '../redux/actions'
	import * as selectors from '../redux/selectors'

	export function LoginScreen() {
	const dispatch = useDispatch()

	// Demo: https://snack.expo.io/@brunolemos/touch-button-scale-effect

	import React from 'react'
	import { Animated, StyleProp, TouchableWithoutFeedback, TouchableWithoutFeedbackProps, ViewStyle } from 'react-native'
	import { styleMerge } from 'shared/src/utils'

	export interface TouchableScaleProps extends TouchableWithoutFeedbackProps {
	containerStyle?: StyleProp<ViewStyle>
	}

	func autocomplete(index, Type, term string) []string {
	client, _ := elastic.NewSimpleClient(elastic.SetURL("http://00.00.00.00:9200"),
	elastic.SetErrorLog(log.New(os.Stderr, "ELASTIC ", log.LstdFlags)),
	elastic.SetInfoLog(log.New(os.Stdout, "", log.LstdFlags)))

	ctx := context.Background()

	tagSuggester := elastic.NewCompletionSuggester("sticker-suggest").Fuzziness(0).Text(term).Field("tags").SkipDuplicates(true)

	searchSource := elastic.NewSearchSource().

	package main

	/*
	® 2018 - Felipe Henrique - All rigths reserved
	Algoritmo de arvore binária
	*/

	import (
	"fmt"
	)

	version: 2
	jobs:
	build_and_test:
	docker:
	- image: circleci/node:10
	working_directory: ~/repo
	steps:
	- checkout
	- restore_cache:
	keys:

	version: 2
	jobs:
	build:
	working_directory: ~/your-project-name
	docker:
	- image: circleci/node:9.11
	steps:
	- checkout
	- setup_remote_docker
	- run: