Javascript 无法读取 null 的属性推送
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Cannot read property push of null
提问by forgottofly
while pushing an element for the first time to a child array which is null,I'm getting this error "Cannot read property push of null" But the element gets pushed,and the second time I do everything goes fine.It gets added to the array
当第一次将一个元素推送到一个为空的子数组时，我收到这个错误“无法读取 null 的属性推送”但是元素被推送了，第二次我做的一切都很好。它被添加到数组
this.group.departmentsList.push({
name: group.newCategoryName,
sortOrder: group.departmentsList.length,
type: "category"
});
group contains the data and departmentList is the child array which is declared like this:
group 包含数据，departmentList 是子数组，声明如下：
$scope.parentDepartment = [
{
departmentsList: [{}]
}
];
回答by dfsq
Well don't push to nonexistent array maybe? You can explicitly check if it's not null and create one if needed:
好吧，也许不要推送到不存在的数组？您可以明确检查它是否不为 null 并在需要时创建一个：
this.group.departmentsList = this.group.departmentsList || [];
this.group.departmentsList.push({
name: group.newCategoryName,
sortOrder: group.departmentsList.length,
type: "category"
});
