For efficiency reasons we often put several different data types (`RNode`, `LView`, `LContainer`,
`StylingContext`) in same location in `LView`. This is because we don't want to pre-allocate
space
for it because the storage is sparse. This file contains utilities for dealing with such data
types.
How do we know what is stored at a given location in `LView`.
- `Array.isArray(value) === false` => `RNode` (The normal storage value)
- `Array.isArray(value) === true` => than the `value[0]` represents the wrapped value.
- `typeof value[TYPE] === 'object'` => `LView`
- This happens when we have a component at a given location
- `typeof value[TYPE] === 'number'` => `StylingContext`
- This happens when we have style/class binding at a given location.
- `typeof value[TYPE] === true` => `LContainer`
- This happens when we have `LContainer` binding at a given location.
NOTE: it is assumed that `Array.isArray` and `typeof` operations are very efficient.
PR Close#28947
`LView`, `LContainer`, `StylingContext` are all arrays which wrap either
an `HTMLElement`, `LView`, `LContainer`, `StylingContext`. It is often
necessary to retrieve the correct type of element from the location
which means that we often have to wrap the arrays. Logically it makes
more sense if the thing which we are wrapping is at `0` location. Also
it may be more performant since data is more local which may result in
more L2 cache hits in CPU.
PR Close#28947
Up until now, `[style]` and `[class]` bindings (the map-based ones) have only
worked as template bindings and have not been supported at all inside of host
bindings. This patch ensures that multiple host binding sources (components and
directives) all properly assign style values and merge them correctly in terms
of priority.
Jira: FW-882
PR Close#28246
