typescript 的有趣语法

[pengkobe]

说是有趣，其实就是语法糖啦。

泛型

function identity<T>(arg: T): T {
    return arg;
}

联合类型

 string | number

高级类型

function extend<T, U>(first: T, second: U): T & U {
    let result = <T & U>{};
    for (let id in first) {
        (<any>result)[id] = (<any>first)[id];
    }
    for (let id in second) {
        if (!result.hasOwnProperty(id)) {
            (<any>result)[id] = (<any>second)[id];
        }
    }
    return result;
}