javascript - 未捕获的类型错误 : Cannot set property 'product_id' of undefined

Question

我正在尝试在 jQuery 中创建一个多维数组。

var parent = $(this).parents(".product:first").find(".decking_var_content > li");
var product_id = $(this).parents('.product:first').find( '.variations_form').find('input[name=product_id]').val();
var myarray = [];

parent.each(function() {
    var var_id = $(this).find("span").attr("data-id");
    var quantity = $(this).find(".decking_var_child_ul").find("input[name=quantity]").val();

    if (var_id) {   
        myarray[var_id]['product_id'] = product_id; //error points here
        myarray[var_id]['quantity'] = quantity;
        myarray[var_id]['variation_id'] = var_id;
    } 
    else {
        myarray[product_id]['quantity'] = quantity;
    }
});

错误指向此 myarray[var_id]['product_id'] = Product_id; 。 我已提醒 product_id 所以我知道它有一个值。

如何解决这个问题？

Answer 1

您需要在设置其属性之前通过在其中创建一个对象来初始化myarray[var_id]:

if (var_id) {  
    myarray[var_id] = {}; 
    myarray[var_id]['product_id'] = product_id;
    myarray[var_id]['quantity'] = quantity;
    myarray[var_id]['variation_id'] = var_id;
} 
else {
    myarray[product_id] = {};
    myarray[product_id]['quantity'] = quantity;
}

请注意，您可以使此代码更加简洁，如下所示:

if (var_id) {  
    myarray[var_id] = {
        'product_id': product_id,
        'quantity': quantity,
        'variation_id': var_id
    }; 
} 
else {
    myarray[product_id] = {
        'quantity': quantity
    };
}