i18u iahu

怎么编写一个高可用的前端组件

React 流行以后，编写前端组件的成本变得非常低廉，开发一个通用组件是件非常容易的事，日常业务开发也早已变成搭积木式的堆组件了。在这种开发环境下组件的可用性就变得至关重要，谁都希望拿在手的组件可以像橡皮泥一样”任人摆布“，“放之四海皆准”，而不是动不动就要去改源码。

高可用包含两层意思，

一是开发时的高可用，一处编码，处处可用

二是用户群体的高可用，正常用户行为可用，特殊用户行为也可用。

	export const getImageData = (image: HTMLImageElement) => {
	const canvas = document.createElement('canvas');
	const ctx = canvas.getContext('2d') as CanvasRenderingContext2D;
	const width = image.width;
	const height = image.height;

	if (width === 0 \|\| height === 0) throw new Error('image dimensions cannot be zero');

	canvas.width = width;
	canvas.height = height;

	/**
	* Returns SHA-256 hash from supplied message.
	*
	* @param {String} message.
	* @returns {String} hash as hex string.
	*
	* @example
	* sha256('abc').then(hash => console.log(hash));
	* const hash = await sha256('abc');
	*/

	import fs from 'fs'
	import glob from 'glob'
	import cliProgress from 'cli-progress'
	import getThemeColor from './main'
	import ProHub from './prohub'

	const [path] = process.argv.slice(2)
	const bar = new cliProgress.SingleBar({}, cliProgress.Presets.shades_classic)

	glob(path, function (err, matches) {

	type Job<T> = () => Promise<T>
	export const promiseThrottle = async <T>(
	jobs: Job<T>[],
	parallelCount: number,
	onParallelDone?: (results: T[], index: number) => void
	): Promise<T[]> => {
	if (!(jobs && Array.isArray(jobs))) {
	return Promise.reject('jobs must be Array')
	}

	import * as crypto from 'crypto'

	const HMAC_ALGORITHM = 'HmacSHA1'
	const ekey = Buffer.from('9527')
	const ikey = Buffer.from('2840')

	const mergeBytes = (...args: Uint8Array[]) => {
	return Buffer.concat(args)
	}

	Installing CYGWIN with SSH
	1) Download cygwin setup.exe from http://www.cygwin.com
	- Execute setup.exe
	- Install from internet
	- Root directory: `c:\cygwin` + all users
	- Local package directory: use default value
	- Select a mirror to download files from
	- Select these packages:
	- editors > xemacs 21.4.22-1
	- net > openssh 6.1-p

	import memoize from 'lodash/memoize';

	const supportLocaleCompare = typeof String.prototype.localeCompare === 'function';
	const getShengmu = memoize((c: string) => {
	const MAP = 'abcdefghjklmnopqrstwxyz';
	const boundaryChar = '驁簿錯鵽樲鰒餜靃攟鬠纙鞪黁漚曝裠鶸蜶籜鶩鑂韻糳';

	if (!supportLocaleCompare) {
	return c;
	}