Json数组错误无法设置undefined的属性'model'

var temp = [{}]
var as = ['a', 'b']
for (i = 0; i < as.length; i++) {
    temp[i].model = as[i]
}

I'm getting the following error:

我收到以下错误:

Cannot set property 'model' of undefined

无法设置未定义的属性“模型”

5 个解决方案

#1

Okay, this should do the trick for you:

好的,这应该为你做的伎俩:

var temp = [];
var as = ['a', 'b'];
for (i = 0; i < as.length; i++) {
    temp[i] = temp[i] || {};
    temp[i].model = as[i];
}

Because as can be longer than temp, you need to make sure temp[i] exists, which is exactly what temp[i] = temp[i] || {}; does:

因为可能比temp更长,你需要确保temp [i]存在,这正是temp [i] = temp [i] || {};作用:

If temp[i] exists, it does nothing.

如果temp [i]存在,它什么都不做。

If temp[i] doesn't exist, it assigns a new empty object ({}) to temp[i].

如果temp [i]不存在,则为temp [i]分配一个新的空对象({})。

Notice that I removed the {} from temp = [{}] --> temp = []. You don't need that first empty object in there, now.

请注意,我从temp = [{}] - > temp = []中删除了{}。你现在不需要第一个空对象。

If you're absolutely certain temp will never contain any values before the loop, you can just do this instead:

如果你绝对确定temp在循环之前永远不会包含任何值,你可以这样做:

for (i = 0; i < as.length; i++) {
    temp[i] = { model: as[i] };
}

Or:

temp = as.map(function(item){ return { model: item }});

#2

Length of temp is 1, length of as is 2. temp[1] is thus undefined.

temp的长度为1,长度为2.因此temp [1]是不确定的。

I think this communicates the intention of the code better, and is correct:

我认为这更好地传达了代码的意图,并且是正确的:

var temp = [];
var as = ['a', 'b'];

for (var i = 0; i < as.length; i++) {
    temp[i] = {model: as[i]};
}

#3

To always have enough values in temp you could populate it beforehand:

要始终在temp中有足够的值,您可以事先填充它:

var as = ['a', 'b'];
var temp = as.map(function() { return {}; });
for (i = 0; i < as.length; i++) {
    temp[i].model = as[i]
}

#4

Try this

var temp = [];
var as = ['a', 'b']
for (i = 0; i < as.length; i++) {
    temp.push({'model':as[i]});
}
console.log(temp);

Fiddle

#5

this is very simple.

这很简单。

use this below for your problem.

使用以下内容解决您的问题。

> var temp =[[]]; var as = ['a','b'] for(i=0;i<as.length;i++){  
> temp.push({model : as[i]}) }
> 
> console.log(temp)

Let me know if you have any clarification

如果您有任何澄清,请告诉我

#1