t-call-context is a feature that's supposed to mask the rendering
context completely, but currently the component remains available
through `this`.
This commit stops treating `this` as a reserved word, so that it's
compiled to a lookup in the rendering context, and adds `this` to the
rendering context when binding the component's rendering function. With
these changes, `this` behaves the same as before when outside a
t-call-context, but when the rendering context is overriden, the
template can no longer access `this`. `this` still represents the
instance of the component inside of the rendering function since it's
needed by owl internally.
A side-effect of this change is that now the rendering context is no
longer the instance of the component by default, but is always an object
with the component in its prototype chain. This was already the case
before in some contexts (eg inside t-foreach, or inside components with
a t-set/t-call anywhere in its template). This can cause issues in rare
cases when a component method was called directly on the rendering
context, as before this change, the method's bound this would be the
component instance (except in a t-foreach, component with a
t-set/t-call, etc), while after this change it is now never the
component instance. When the method only reads on `this` there is no
issue as all the components properties are available on the rendering
contexts, but setting a value on `this` will write on the rendering
context and not the component which is likely a mistake.
While this is a breaking change, simply adding a t-set/t-call to any
template would break components that would be broken by this change,
with this in mind we decided to make this change anyway so that
developers get the error as early as possible in the development cycle
rather than having a seemingly inocuous change break code under them.
In app.js, `mount(Root, document.body, { dev: true, env });` crash because `body` is not available yet.
Therefore, moving the script into the body fix the issue.
From the beginning, Owl was designed to only call event handler on
components that are mounted in the DOM. The main benefit is that if a
component is destroyed, we are guaranteed to not execute any useless (or
potentially dangerous code).
However, there is one downside: if a component tree is being mounted,
and a child component trigger an event in its mounted hook, then it
cannot be caught by the parent, since the parent is technically not yet
mounted.
This may not be a good situation, but the point is that Owl
unnecessarily prevent the handler to be called.
We can fix this issue by simply checking if the component is not destroyed
instead of checking that it is mounted.
closes#809
In most cases, we just want Component<any, Env>. But since it was so
annoying to have always the type Env, we actually used
Component<any,any> everywhere.
With this commit, the generic types have a default (and their order is
swapped), so we can simply use Component in most cases, and
Component<Props> when we want to type the props.
including:
- add a link to the tutorial in the main readme page
- remove learning page on 'env', move content on reference page
- add dynamic sub components section in component page
- add reference page on props
- split qweb page into engine/language pages
- move t-key information into qweb language page
Samuel Degueldre