AngularJS：严格模式之外尚不支持块范围的声明（let，const，函数，类）

Question

So I had this directive:

app.directive('customDropdown', function() {
    return {
        restrict: 'E',
        templateUrl: '/static/templates/directive_templates/customdropdown.html',
        link: function(scope, element, attrs) {
            console.log(attrs.custom-class);
        }
    }
})

Markup:

<custom-dropdown custom-class="custom-select-menu">

</custom-dropdown>

But, due to console.log(attrs.custom-class) I get the error mentioned in the question. It goes away when I change custom-class to just custom . Any idea why the error was popping up? Can't use hyphens?

Answer 1

attrs.custom-class custom-class is not a valid identifier in javascript. So you have 2 choices :

• Rename custom-class into something else without an hypen.

• Use the bracket syntax : attrs['custom-class']

Answer 2

This means that you must declare strict mode by writing "use strict" at the beginning of the file or the function to use block-scope declarations.

function test(){
    "use strict";
    let a = 1;
}