js 实现函数重载

[Sogrey]

function createOverLoad () {
    const callMap = new Map();
    function overLoad (...args) {
        const key = args.map(arg => typeof arg).join(',');
        const fn = callMap.get(key);
        if (fn) {
            return fn.apply(this, args);
        }
        throw "No match function."
    }
    overLoad.addImpl = function (...args) {
        if (args.length == 0) return;
        const fn = args.pop();
        if (!fn || typeof fn !== 'function') {
            return;
        }
        const types = args;
        callMap.set(types.join(','), fn);
    }

    return overLoad
}

const getUsers = createOverLoad();

getUsers.addImpl(() => {
    console.log("无参")
})

const searchPage = (page, size = 10) => {
    console.log("查询页码和数量", page, size)
}

getUsers.addImpl('number', searchPage)
getUsers.addImpl('number', 'number', searchPage)

getUsers.addImpl('string', (name) => {
    console.log("根据用户名查询", name)
})
getUsers.addImpl('string', 'string', (name, sex) => {
    console.log("根据用户名和性别查询", name, sex)
})

getUsers()
getUsers(1)
getUsers(1, 20)
getUsers("张三")
getUsers("张三", "女")

返回：

无参
查询页码和数量 1 10
查询页码和数量 1 20
根据用户名查询 张三
根据用户名和性别查询 张三 女