无法读取 null 的属性推送 [英] Cannot read property push of null

问题描述

第一次将元素推送到为空的子数组时，出现此错误无法读取 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.它被添加到数组中

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

this.group.departmentsList.push({
    name: group.newCategoryName,
    sortOrder: group.departmentsList.length,
    type: "category"
});

group 包含数据，departmentList 是子数组，声明如下:

group contains the data and departmentList is the child array which is declared like this:

 $scope.parentDepartment = [
    {
        departmentsList: [{}]
    }
];

推荐答案

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:

Well don't push to nonexistent array maybe? You can explicitly check if it's not null and create one if needed:

this.group.departmentsList = this.group.departmentsList || [];
this.group.departmentsList.push({
    name: group.newCategoryName,
    sortOrder: group.departmentsList.length,
    type: "category"
});

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