Previously we would write to class/style as strings `element.className` and `element.style.cssText`. Turns out that approach is good for initial render but not good for updates. Updates using this approach are problematic because we have to check to see if there was an out of bound write to style and than perform reconciliation. This also requires the browser to bring up CSS parser which is expensive.
Another problem with old approach is that we had to queue the DOM writes and flush them twice. Once on element advance instruction and once in `hostBindings`. The double flushing is expensive but it also means that a directive can observe that styles are not yet written (they are written after directive executes.)
The new approach uses `element.classList.add/remove` and `element.style.setProperty/removeProperty` API for updates only (it continues to use `element.className` and `element.style.cssText` for initial render as it is cheaper.) The other change is that the styling changes are applied immediately (no queueing). This means that it is the instruction which computes priority. In some circumstances it may result in intermediate writes which are than overwritten with new value. (This should be rare)
Overall this change deletes most of the previous code and replaces it with new simplified implement. The simplification results in code savings.
PR Close#34804
NOTE: This change must be reverted with previous deletes so that it code remains in build-able state.
This change deletes old styling code and replaces it with a simplified styling algorithm.
The mental model for the new algorithm is:
- Create a linked list of styling bindings in the order of priority. All styling bindings ere executed in compiled order and than a linked list of bindings is created in priority order.
- Flush the style bindings at the end of `advance()` instruction. This implies that there are two flush events. One at the end of template `advance` instruction in the template. Second one at the end of `hostBindings` `advance` instruction when processing host bindings (if any).
- Each binding instructions effectively updates the string to represent the string at that location. Because most of the bindings are additive, this is a cheap strategy in most cases. In rare cases the strategy requires removing tokens from the styling up to this point. (We expect that to be rare case)S Because, the bindings are presorted in the order of priority, it is safe to resume the processing of the concatenated string from the last change binding.
PR Close#34616
NOTE: This change deletes code and creates a BROKEN SHA. If reverting this SHA needs to be reverted with the next SHA to get back into a valid state.
PR Close#34616
The `computeStaticStyling` will be used for computing static styling value during `firstCreatePass`.
The function takes into account static styling from the template as well as from the host bindings. The host bindings need to be merged in front of the template so that they have the correct priority.
PR Closes#34418
Parsing styling is now simplified to be used like so:
```
for (let i = parseStyle(text); i <= 0; i = parseStyleNext(text, i)) {
const key = getLastParsedKey();
const value = getLastParsedValue();
...
}
```
This change makes it easier to invoke the parser from other locations in the system without paying the cost of creating and iterating over `Map` of styles.
PR Closes#34418
This adds `insertTStyleValue` but does not hook it up to anything yet.
The purpose of this function is to create a linked-list of styling
related bindings. The bindings can be traversed during flush.
The linked list also keeps track of duplicates. This is important
for binding to know if it needs to check other styles for reconciliation.
PR Close#34004
This change introduces class/style reconciliation algorithm for DOM elements.
NOTE: The code is not yet hooked up, it will be used by future style algorithm.
Background:
Styling algorithm currently has [two paths](https://hackmd.io/@5zDGNGArSxiHhgvxRGrg-g/rycZk3N5S)
when computing how the style should be rendered.
1. A direct path which concatenates styling and uses `elemnent.className`/`element.style.cssText` and
2. A merge path which uses internal data structures and uses `element.classList.add/remove`/`element.style[property]`.
The situation is confusing and hard to follow/maintain. So a future PR will remove the merge-path and do everything with
direct-path. This however breaks when some other code adds class or style to the element without Angular's knowledge.
If this happens instead of switching from direct-path to merge-path algorithm, this change provides a different mental model
whereby we always do `direct-path` but the code which writes to the DOM detects the situation and reconciles the out of bound write.
The reconciliation process is as follows:
1. Detect that no one has modified `className`/`cssText` and if so just write directly (fast path).
2. If out of bounds write did occur, switch from writing using `className`/`cssText` to `element.classList.add/remove`/`element.style[property]`.
This does require that the write function computes the difference between the previous Angular expected state and current Angular state.
(This requires a parser. The advantage of having a parser is that we can support `style="width: {{exp}}px" kind of bindings.`)
Compute the diff and apply it in non destructive way using `element.classList.add/remove`/`element.style[property]`
Properties of approach:
- If no out of bounds style modification:
- Very fast code path: Just concatenate string in right order and write them to DOM.
- Class list order is preserved
- If out of bounds style modification detected:
- Penalty for parsing
- Switch to non destructive modification: `element.classList.add/remove`/`element.style[property]`
- Switch to alphabetical way of setting classes.
PR Close#34004
This patch gets rid of the configuration settings present in the
`TStylingContext` array that is used within the styling algorithm
for `[style]`, `[style.prop]`, `[class]` and `[class.name]` bindings.
These configurations now all live inside of the `TNodeFlags`.
PR Close#33540
This patch ensures that the `[style]` and `[class]` based bindings
are directly applied to an element's style and className attributes.
This patch optimizes the algorithm so that it...
- Doesn't construct an update an instance of `StylingMapArray` for
`[style]` and `[class]` bindings
- Doesn't apply `[style]` and `[class]` based entries using
`classList` and `style` (direct attributes are used instead)
- Doesn't split or iterate over all string-based tokens in a
string value obtained from a `[class]` binding.
This patch speeds up the following cases:
- `<div [class]>` and `<div class="..." [class]>`
- `<div [style]>` and `<div style="..." [style]>`
The overall speec increase is by over 5x.
PR Close#33336
Prior to this fix, all style/class bindings (e.g. `[style]` and
`[class.foo]`) would quietly update a binding value if and when the
current binding value changes during checkNoChanges.
With this patch, all styling instructions will properly check to see
if the value has changed during the second pass of detectChanges()
if checkNoChanges is active.
PR Close#33103
This patch introduces the `printTable()` and `printSources()`
methods to `DebugStylingContext` which can be used via the
`window.ng.getDebugNode` helpers when debugging an application.
PR Close#33179
Prior to this fix, whenever a style or class binding is present, the
binding application process would require an instance of `TStylingContext`
to be built regardless of whether or not any binding resolution is needed
(just so that it knows whether or not there are any collisions).
This check is, however, unnecessary because if (and only if) there
are directives present on the element then are collisions possible.
This patch removes the need for style/class bindings to register
themselves on to a `TStylingContext` if there are no directives and
present on an element. This means that all map and prop-based
style/class bindings are applied as soon as bindings are updated on
an element.
PR Close#32919
This patch introduces the `printTable()` and `printSources()`
methods to `DebugStylingContext` which can be used via the
`window.ng.getDebugNode` helpers when debugging an application.
PR Close#32753
This patch is a final major refactor in styling Angular.
This PR includes three main fixes:
All temporary state taht is persisted between template style/class application
and style/class application in host bindings is now removed.
Removes the styling() and stylingApply() instructions.
Introduces a "direct apply" mode that is used apply prop-based
style/class in the event that there are no map-based bindings as
well as property collisions.
PR Close#32259
PR Close#32591
This patch is a final major refactor in styling Angular.
This PR includes three main fixes:
All temporary state taht is persisted between template style/class application
and style/class application in host bindings is now removed.
Removes the styling() and stylingApply() instructions.
Introduces a "direct apply" mode that is used apply prop-based
style/class in the event that there are no map-based bindings as
well as property collisions.
PR Close#32259
PR Close#32596
This patch is a final major refactor in styling Angular.
This PR includes three main fixes:
All temporary state taht is persisted between template style/class application
and style/class application in host bindings is now removed.
Removes the styling() and stylingApply() instructions.
Introduces a "direct apply" mode that is used apply prop-based
style/class in the event that there are no map-based bindings as
well as property collisions.
PR Close#32259
This commit is the final patch of the ivy styling algorithm refactor.
This patch swaps functionality from the old styling mechanism to the
new refactored code by changing the instruction code the compiler
generates and by pointing the runtime instruction code to the new
styling algorithm.
PR Close#30742
This patch is one of the final patches to refactor the styling algorithm
to be more efficient, performant and less complex.
This patch enables sanitization support for map-based and prop-based
style bindings.
PR Close#30667
This patch in the second runtime change which refactors how styling
bindings work in Angular. This patch refactors how map-based
`[style]` and `[class]` bindings work using a new algorithm which
is faster and less complex than the former one.
This patch is a follow-up to an earlier refactor which enabled
support for prop-based `[style.name]` and `[class.name]`
bindings (see f03475cac8).
PR Close#30543
This is the first refactor PR designed to change how styling bindings
(i.e. `[style]` and `[class]`) behave in Ivy. Instead of having a heavy
element-by-element context be generated for each element, this new
refactor aims to use a single context for each `tNode` element that is
examined and iterated over when styling values are to be applied to the
element.
This patch brings this new functionality to prop-based bindings such as
`[style.prop]` and `[class.name]`.
PR Close#30469
Miško Hevery
Matias Niemelä