se7en se7en00

TS原生的Readonly只会限制一层写入操作，我们可以利用递归来实现深层次的Readonly。但要注意，TS对最大递归层数做了限制，最多递归5层。

type DeepReadony<T> = {
    readonly [P in keyof T]: DeepReadony<T[P]>
}

interface SomeObject {
  a: {
    b: {
 c: number;

我在项目中遇到这样一种场景，需要获取一个类型中所有value为指定类型的key。例如，已知某个React组件的props类型

interface SomeProps {
    a: string
    b: number
    c: (e: MouseEvent) => void
    d: (e: TouchEvent) => void
}

Say we have a prop.users of the shape:

const users = [
    {username: 'bob', age: 30, tags: [{name: 'work', id: 1}, {name: 'boring', id: 2}]},
    {username: 'jim', age: 25, tags: [{name: 'home', id: 3}, {name: 'fun', id: 4}]},
    {username: 'jane', age: 30, tags: [{name: 'vacation', id: 5}, {name: 'fun', id: 4}]}
];

Either you use .babelrc to specify environment specific settings (plugins or transforms for example) using the env key:

{
  "presets": ["es2015", "stage-0", "react"],
  "env": {
    "development": {
      "plugins": [
        ["transform-object-rest-spread"],
 ["transform-react-display-name"],

	import axios, { AxiosRequestConfig, AxiosResponse } from 'axios';
	import { Observable } from 'rxjs';

	const fromRequest = (request: AxiosRequestConfig) =>
	new Observable<AxiosResponse>(
	(o) => {
	const source = axios.CancelToken.source();

	o.add(() => source.cancel('Operation canceled by the user.'));

	"use strict";

	/**
	* Hypertext Transfer Protocol (HTTP) response status codes.
	* @see {@link https://en.wikipedia.org/wiki/List_of_HTTP_status_codes}
	*/
	enum HttpStatusCode {

	/**
	* The server has received the request headers and the client should proceed to send the request body

	/* eslint-disable prefer-template */

	const path = require('path');
	const aliases = require('./aliases');

	// ///////////////////////////////////////////////////////////////
	// ////////////////// PLUGINS ////////////////////////////////
	// ///////////////////////////////////////////////////////////////

	const commonPlugins = [

	/**
	@description 页面垂直平滑滚动到指定滚动高度
	@author zhangxinxu(.com)
	*/
	var scrollSmoothTo = function (position) {
	if (!window.requestAnimationFrame) {
	window.requestAnimationFrame = function(callback, element) {
	return setTimeout(callback, 17);
	};
	}

	今天看到一个数组的声明是这样的：
	var dotenvFiles = [
	`${paths.dotenv}.${NODE_ENV}.local`,
	`${paths.dotenv}.${NODE_ENV}`,
	NODE_ENV !== 'test' && `${paths.dotenv}.local`,
	paths.dotenv,
	].filter(Boolean);
	//result:
	//['XX/XX.local', 'XX/XX']

	//大写单词的首字母
	const capitalize = (str, lowerRest = false) => str.slice(0, 1).toUpperCase() + (lowerRest ? str.slice(1).toLowerCase() : str.slice(1));

	// capitalize(‘myName’, true) -> ‘Myname’
	//note: 使用slice（0,1）和toUpperCase（）大写第一个字母，slice（1）获取字符串的其余部分.

	//大写每个单词的首字母
	const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase());