javascript - 如何使用 javascript 循环对象数组？

Question

我试图循环一个包含对象的数组，但我不断收到错误:“无法设置未定义的属性‘颜色’”。我做错了什么？

var ObjectTest = function(something1, something2){
    this.Name = something1;
    this.Job = something2;
    this.color = '';
    this.numbers = [];
    
}

var first = new ObjectTest('Paul', 'teacher');
var second = new ObjectTest('Jane', 'doctor');
var third = new ObjectTest('Mike', 'student');

var someArray = [];
someArray.push(first, second, third);
console.log(someArray);


for(var i =0; i <= someArray.length; i++){
    someArray[i].color = 'red';
};

Answer 1

您需要迭代直到数组的长度但不能结束，因为索引是从零开始的

for (var i = 0; i < someArray.length; i++) {
//                ^

对于不存在的项目，数组返回未定义。 undefined 没有可以分配新值的属性。

var ObjectTest = function(something1, something2) {
        this.Name = something1;
        this.Job = something2;
        this.color = '';
        this.numbers = [];
    };

var first = new ObjectTest('Paul', 'teacher');
var second = new ObjectTest('Jane', 'doctor');
var third = new ObjectTest('Mike', 'student');

var someArray = [];
someArray.push(first, second, third);

for (var i = 0; i < someArray.length; i++) {
    someArray[i].color = 'red';
}                                            // no semicolon here

console.log(someArray);