Typescript 小问题汇总

namespace Validation {
    export interface StringValidator {
        isAcceptable(s: string): boolean;
    }

    const lettersRegexp = /^[A-Za-z]+$/;
    const numberRegexp = /^[0-9]+$/;

    export class LettersOnlyValidator implements StringValidator {
        isAcceptable(s: string) {
            return lettersRegexp.test(s);
        }
    }

    export class ZipCodeValidator implements StringValidator {
        isAcceptable(s: string) {
            return s.length === 5 && numberRegexp.test(s);
        }
    }
}

// Some samples to try
let strings = ["Hello", "98052", "101"];

// Validators to use
let validators: { [s: string]: Validation.StringValidator; } = {};
validators["ZIP code"] = new Validation.ZipCodeValidator();
validators["Letters only"] = new Validation.LettersOnlyValidator();

// Show whether each string passed each validator
for (let s of strings) {
    for (let name in validators) {
        console.log(`"${ s }" - ${ validators[name].isAcceptable(s) ? "matches" : "does not match" } ${ name }`);
    }
}

下面这句乍一看有点糊涂，啥意思！

let validators: { [s: string]: Validation.StringValidator; } = {};

分析一下，

定义一个validators的对象，类型是一个字面量的对象，对象的键值是字符串类型 [s:string]，对应的值是Validation.StringValidator，命名空间下的接口对象。

相当于

let 对象名：｛[对象键值及类型]：对应的值｝=空对象。