let someArray = [1, "string",false];for(let entry of someArray) { console.log(entry);//1, "string", false} 二、for..in 方法 这个方法要注意和for..of的区别,for..in遍历的值是数组的索引 let list = [4, 5, 6];//for infor(let iinlist) { console.log(i);//"0", "1", "2...
functionLogOutput(tarage:Function,key:string,descriptor:any){letoriginalMethod=descriptor.value;letnewMethod=function(...args:any[]):any{letresult:any=originalMethod.apply(this,args);if(!this.loggedOutput){this.loggedOutput=newArray<any>();}this.loggedOutput.push({method:key,parameters:args,outpu...
type EventContext={value:string;};functiononEvent(eventName:string,eventCallback:(target:EventContext)=>void){
function padLeft(value: string, padding: string | number) { if (typeof padding === "number") { return Array(padding + 1).join(" ") + value; } if (typeof padding === "string") { return padding + value; } throw new Error(`Expected string or number, got '${padding}'.`); }...
val && typeof val === "object" && "x" in val && "y" in val && typeof val.x === "number" && typeof val.y === "number"; } } function f(value: unknown) { if (value instanceof Point) { // Can access both of these - correct! value.x; value.y; // Can't access ...
functionsanitizeFoo(checker:any){if(typeofchecker.number!="number"||typeofchecker.boolean!="boolean"||(checker.maybeString!=undefined&&typeofchecker.maybeString!="string")||!sanitizeBar(checker.bar)){returnfalse;}returntrue;}functionsanitizeBar(checker:any){if(!sanitizenumberArray(checker.numbers)...
let g5: string = getValue3<string>('4'); 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 3. 泛型类型 前面我们使用过Array<类型>来定义数组的类型,这里的Array也是一种类型。
getTokenValue: () => tokenValue, // ... scan, // ... }; 我们通过createScanner创建扫描器之后, 需要对源代码进行扫描操作, 对应源码中的scan函数。我们继续找到scan函数的逻辑, 因为createScanner函数里面只是定义了一些函数, 并没有实质上的逻辑流程进展。
function sum(nums: number[]): number: Use ReadonlyArray if a function does not write to its parameters. interface Foo { new(): Foo; }: This defines a type of objects that are new-able. You probably want declare class Foo { constructor(); }. const Class: { new(): IClass; }: ...
TypeScript Version: 3.0.3 Search Terms: Type based on values in array Is there a current or planned feature to create a type from strings in an array? Code const values = ['A', 'B'] type Foo = OneOf<values> // Is there a way of doing thi...