Question

function extend(...args)，如果我运行该函数并在其中传递空对象

function extend({})，如何检查它是否为空或未定义。

输入：const first = { x: 2, y: 3}; const second = { a: 70, x: 4, z: 5 }; const third = { x: 0, y: 9, q: 10 }; const firstSecondThird = extend(first, second, third);

预期输出：{ x: 2, y: 3, a: 70, z: 5, q: 10 } 我还必须检查...args中的每个条目，它是否是对象而不是未定义的；如果未定义，则必须抛出错误。我还必须检查至少有两个参数。

Answer 1

您可以检查g++中的length来检查Object.keys。 {}是Boolean({})。
使用true检查includes()包含args还是null
使用undefined和some()检查数组的所有元素是否都是typeof。
您不希望您的属性在出现两次时被覆盖。然后，您可以object

reverse()

最重要的是，if语句可以组合为一个语句。

Answer 2

您可以为预期的输出实现它。

const first = { x: 2, y: 3 }; 
const second = { a: 70, x: 4, z: 5 };  
const third = { x: 0, y: 9, q: 10 };
const fourth = undefined;

const firstSecondThird = extend(first, second, third, fourth);

function extend (...args) {
    let result = Object.assign({}, ...args.reverse()); 
    if (result.length < 2) throw ("Length is less than 2");
    if (args.includes(undefined) || args.includes(null)) throw ("args contains undefined")
    return result;
}

console.log(firstSecondThird)

const first = { x: 2, y: 3 }; 
const second = { a: 70, x: 4, z: 5 };  
const third = { x: 0, y: 9, q: 10 };

const firstSecondThird = extend(first, second, third);

function extend (...args) {
    let result = Object.assign({}, ...args.reverse()); 
    if (result.length < 2) throw ("Length is less than 2");
    if (args.includes(undefined) || args.includes(null)) throw ("args contains undefined")
    return result;
}

console.log(firstSecondThird)

如何检查通过rest参数传递的对象是否为null或未定义？

2 个答案: