[英]Cannot add item to array
如何将新项目添加到数组? 我正在尝试添加一个项目,但它返回一个错误。 请参阅下面的屏幕截图和我的代码。
JavaScript 代码
var roles = [{id: 8, display_name: "test", description: "test", created_at: "2020-02-20 11:34:22", updated_at: "2020-02-20 11:34:22"}
8: {id: 9, display_name: "ASDASD", description: "ADASD", created_at: "2020-02-20 11:39:08", updated_at: "2020-02-20 11:39:08"}
9: {id: 10, display_name: "Test1", description: "test1", created_at: "2020-02-20 11:44:01", updated_at: "2020-02-20 11:44:01"}
10: {id: 11, display_name: "Test2", description: "test2", created_at: "2020-02-21 04:18:49", updated_at: "2020-02-21 04:18:49"}
11: {id: 12, display_name: "Test3", description: "test3", created_at: "2020-02-21 06:56:52", updated_at: "2020-02-21 06:56:52"}
12: {id: 13, display_name: "Test4", description: "test4", created_at: "2020-02-21 07:00:32", updated_at: "2020-02-21 07:00:32"}];
this.roles.id = 12;
this.roles.display_name = 'Mod';
this.roles.description = 'mod';
this.roles.created_at = '2020-02-21 07:12:50';
this.roles.updated_at = '2020-02-21 07:12:50';
错误
类型错误:无法设置未定义的属性“id”
我想要什么:
将项目添加到上面屏幕截图中的数据。
笔记
我正在使用 vueJS,并且在data{}
对象中设置了roles
数据。
看起来this.roles
可能是您正在记录的项目数组,对吗?
所以通过设置this.roles.id = 12;
,您正在尝试设置数组的id
属性,而不是使用这些属性向数组添加新项目。
尝试这个
var newRole = {
id: 12,
display_name: 'Mod',
description: 'mod',
created_at: '2020-02-21 07:12:50',
updated_at: '2020-02-21 07:12:50'
};
this.roles.push(newRole);
这是我最好的猜测。 不过,您确实应该上传有关该问题的更多信息:
这里有一个解决方案,
我已经创建了您的示例角色对象数组,
创建了一个要添加的新对象,
然后将新对象添加到数组中。
let roles = [
{
"id" : 1,
"display_name" : "One",
"description" : "One desc",
"created_at" : "2020-02-21 01:01:01",
"updated_at" : "2020-02-21 01:01:01"
},
{
"id" : 2,
"display_name" : "Two",
"description" : "Two desc",
"created_at" : "2020-02-21 01:01:01",
"updated_at" : "2020-02-21 01:01:01"
}
];
let newRole = {};
newRole.id = 3;
newRole.display_name = "Three";
newRole.description = "Three desc";
newRole.created_at = "2020-02-21 01:01:01";
newRole.updated_at = "2020-02-21 01:01:01";
roles.push(newRole);
您直接尝试将一个对象添加到数组中,
如果您指定索引,您也可以这样做
这是一个 json 元素数组。 您需要先创建一个元素,然后将其推送到这样的角色数组中。
let newElement = {id:12, display_name :'Mod', description : 'mod', created_at:'2020-02-21 07:12:50', updated_at:'2020-02-21 07:12:50'}
this.roles.push(newElement)
由于您使用的是指窗口而不是对象的“this”,因此您遇到了未定义的错误。
您可以手动添加它,因为您已经得到了答案,或者您可以使用 Class 代替,在我看来这会更好地工作,我不认为使用所有这些代码复制是好的,这是我的解决方案:
const roles = [{ id: 8, display_name: "test", description: "test", created_at: "2020-02-20 11:34:22", updated_at: "2020-02-20 11:34:22" },
{ id: 9, display_name: "ASDASD", description: "ADASD", created_at: "2020-02-20 11:39:08", updated_at: "2020-02-20 11:39:08" },
{ id: 10, display_name: "Test1", description: "test1", created_at: "2020-02-20 11:44:01", updated_at: "2020-02-20 11:44:01" },
{ id: 11, display_name: "Test2", description: "test2", created_at: "2020-02-21 04:18:49", updated_at: "2020-02-21 04:18:49" },
{ id: 12, display_name: "Test3", description: "test3", created_at: "2020-02-21 06:56:52", updated_at: "2020-02-21 06:56:52" },
{ id: 13, display_name: "Test4", description: "test4", created_at: "2020-02-21 07:00:32", updated_at: "2020-02-21 07:00:32" }];
class Role {
id;
display_name;
description;
created_at;
updated_at;
constructor(id, display_name, description, created_at, updated_at) {
this.id = id;
this.display_name = display_name;
this.description = description;
this.created_at = created_at;
this.updated_at = updated_at;
}
}
const role1 = new Role(14, "asdas", "asdasd", "2020-02-21", "2020-02-21");
roles.push(role1);
const role2 = new Role(15, "asdasas", "assdasd", "2020-02-21", "2020-02-21");
roles.push(role2);
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