javascript - Angular 5 组件在选择器中需要 `-` 吗？

Question

我正在审核此 Angular 5 forms youtube tutorial在其中，Sebastian 最初将表单选择器命名为 app-form01，但他删除了 app- 部分。 IIUC 自定义元素应该有 -。这是放松了吗？

Answer 1

- 根本不需要。它被认为是良好做法，因为它符合自定义元素要求。除此之外，无论是否使用 -，组件的行为都将完全相同，您还可以使用大小写混合的名称。

另见

• Why does Angular not need a dash in component name

• https://github.com/angular/angular/issues/5968

During the kebab-case removal we kept element selectors dasherized because of custom element spec.

Component name remains dash-cased because a dash is required by the custom element spec, which we use for guidance since even after making Angular templates case-sensitive the templates remain valid html5 fragments (although with higher fidelity due to case-sensitivity that only our html parser can see).

Very few people know about the custom element spec and the guarantees the dash gives us, so I think that it would be better to enforce that all directive/component element selectors have at least a single dash in it. There should be a way to opt out via a flag in the Component/Directive metadata, but it shouldn't be on by default.

If someone is unfamiliar with the custom element spec, the benefits of adding a dash to the element name are:

• the element becomes a custom element - the type of the DOM node is HTMLElement instead of HTMLUnknownElement
• in case we need it, we can benefit from the :unresolved psedo-class by registering a fake element via document.registerElement
• the spec guarantees that browsers will not introduce native elements with a dash in the name, meaning that apps won't break in the future should browsers natively implement an element that matches an Angular Component selector (e.g. )

More info about custom elements.