[ts]泛型
类型变量,一个组件可以支持多种数据类型的数据
基础用法
function identity(arg: T): T { return arg; } const output = identity('myString'); console.log(output);
泛型变量
function identity(arg: T[]): T[] { return arg; }
泛型接口
interface GenericIdentityFn{ (arg: T): T; } function identity (arg: T): T { return arg; } let myIndetity: GenericIdentityFn = identity;
泛型类
class GenericNumber{ zeroValue: T; constructor (value: T) { this.zeroValue = value; } } const myGenericNumer = new GenericNumber (123); console.log(myGenericNumer);
泛型约束
interface Lengthwise { length: number; } function identity(arg: T): T { console.log(arg.length); return arg; }
在泛型中使用类类型
class BeeKeeper { hasMask: boolean; constructor () { this.hasMask = false; } } class ZooKeeper { nametag: string; constructor () { this.nametag = 'tom'; } } class Animal { numLegs: number; constructor () { this.numLegs = 0; } } class Bee extends Animal { keeper: BeeKeeper; constructor () { super(); this.keeper = new BeeKeeper(); } } class Lion extends Animal { keeper: ZooKeeper; constructor () { super(); this.keeper = new ZooKeeper(); } } function createInstance(c: new() => A): A { return new c(); } console.log(createInstance(Lion).keeper.nametag); console.log(createInstance(Bee).keeper.hasMask);