将对象推入循环内的数组中 [英] Pushing an object in an array inside a loop

问题描述

几个小时以来，我一直在试图破解它，但是我似乎无法成功.我正在尝试如下创建一个JSON字符串，但是当将变量obj的值传递给变量j时，我得到的只是该循环的最后结果的数组.

For few hours now I been trying to hack this but I really cant seem to succeed. I am trying to create a JSON string as below, but when passing the values of the variable obj to variable j I am getting an array of only the last result of that loop.

而不是得到诸如以下的结果

instead of getting results such as:

[{machine: "hi"...}
 {machine: "2"....}]

我得到了:

[{machine: "2"...}
 {machine: "2"....
 and keep going with same value}]

我在做什么错了?

var return_json = function(){
    var j = [];
    var obj = {};
    var td;
    for(var i=1;i<tr.length;i++){
        td = tr[i].getElementsByTagName("td");
        obj['machine'] = td[0].innerHTML;
        console.log(obj['machine']);
        obj['day'] = td[1].getElementsByTagName("p")[0].innerHTML;
        obj['night'] = td[2].getElementsByTagName("p")[0].innerHTML;
        j.push(obj);
        console.log(j);
    }
    return j;
};

console.log(save_limitation());

推荐答案

在循环之前，您仅在obj变量中创建单个对象实例.在每次迭代中，您都将更新对象的属性并将相同的对象推入数组.

You're only creating a single object instance in obj variable before the loop. In every iteration, you update the properties of the object and push the same object into your array.

要修复此问题，请在每次迭代时在循环中创建一个新对象.

To fix it, create a new object within your loop at every iteration.

var return_json = function() {
    var j = [];
    var td;
    for(var i = 1; i < tr.length; i++){
        td = tr[i].getElementsByTagName("td");
        j.push({
            machine: td[0].innerHTML,
            day: td[1].getElementsByTagName("p")[0].innerHTML,
            night: td[2].getElementsByTagName("p")[0].innerHTML
        });
    }
    return j;
};

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