The readonly `this` binding applies to every element (and component) and allows to you obtain a reference to rendered elements. For example, we can get a reference to a `<canvas>` element:
The readonly `this` binding applies to every element (and component) and allows you to obtain a reference to rendered elements. For example, we can get a reference to a `<canvas>` element:
```html
<canvas
@ -12,4 +12,4 @@ The readonly `this` binding applies to every element (and component) and allows
></canvas>
```
Note that the value of `canvas` will be `undefined` until the component has mounted, so we put the logic inside the `onMount` [lifecycle function](tutorial/onmount).
Note that the value of `canvas` will be `undefined` until the component has mounted, so we put the logic inside the `onMount` [lifecycle function](tutorial/onmount).
Ordinarily, transitions will play on elements when any container block is added or destroyed. In the example here, toggling the visibility of the entire list also applies transitions to individual list elements.
Instead, we'd like transitions to play only when individual items are added and removed — on other words, when the user drags the slider.
Instead, we'd like transitions to play only when individual items are added and removed — in other words, when the user drags the slider.
We can achieve this with a *local* transition, which only plays when the immediate parent block is added or removed:
@ -12,4 +12,4 @@ We can achieve this with a *local* transition, which only plays when the immedia
Richard Harris
6 years ago