{"compilerOptions":{"target":"es2016",// 编译生成的目标版本代码// "lib": ["esnext","dom","dom.iterable","scripthost"], // 指定我们需要用到的库,也可以不配置,直接根据 target 来获取 /* Specify a set of bundled library declaration files that describe the target runtime environment. */...
'ES5', 'ES6'/'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'"module":"commonjs",// 指定使用模块: 'commonjs', 'amd', 'system', 'umd' or 'es2015'"lib":[],// 指定要包含在编译中的库文件"allowJs":true,// 允许编译 javascript 文件"checkJs":true,// 报告 javascript...
//checkNode方法 核心检测函数(递归调用) export function checkNode(node: ts.Node | undefined, context: FileContext): void { if (node === undefined) { return } if (context.debug) { const { line, character } = ts.getLineAndCharacterOfPosition(context.sourceFile, node.getStart(context.source...
npm add -D @checkdigit/typescript-config Note: you do not need to explicitly install TypeScript itself, as the most recent supported version comes in as a peer dependency of@checkdigit/typescript-config. Make sure your project'stsconfig.jsonextends@checkdigit/typescript-config. Exampletsconfig....
你可以使用 juggle-check,它检查 null 和 undefined,或者使用 strict-check,它返回true设置为null的值,并且不会评估true未定义的变量。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 //juggle if (x == null) { } var a: number; var b: number = null; function check(x, name) { if (x =...
vara:number;varb:number=null;functioncheck(x, name){if(x ==null) {console.log(name +' == null');}if(x ===null) {console.log(name +' === null');}if(typeofx ==='undefined') {console.log(name +' is undefined');}}check(a,'a');chec...
console.log(anExampleVariable); 点击Run 之后就可以直接运行,控制台输出结果显示在右侧,内容如下: [LOG]: "Hello World" 如果你运行成功了,那我们就可以开始接下来的学习了。 下面正式开始介绍。 TypeScript 主要就是在 JavaScript 基础上扩展了一些类型,所以这里就分各种类型来进行介绍。
A type guard is some expression that performs a runtime check that guarantees the type in some scope. 1. 2. typeof类型保护 typeof variable === 'type’是用来确定基本类型的惯用手法,因此TypeScript能够识别typeof,并自动缩窄对应分支下的联合类型: ...
JavaScript is a dynamically typed language. While this makes declaring variables easy, it can in some cases lead to unexpected results. The static type system in TypeScript enables you to describe the shape of an object, providing better documentation, and allowing TypeScript to validate that your...
Finally, as a contributor of TypeScript, your life will likely become a lot easier. Build times will be a lot faster, incremental check times should be faster, and you’ll have a more familiar authoring format if you already write TypeScript code outside of our compiler. ...