Kristiyan Kostadinov 18b33e79d3 perf(core): avoid storing LView in __ngContext__ (#41358)
Currently we save a reference to an `LView` on most DOM nodes created by Angular either by saving
the `LView` directly in the `__ngContext__` or by saving the `LContext` which has a reference to
the `LView`. This can be a problem if the DOM node is retained in memory, because the `LView` has
references to all of the child nodes of the view, as well as other internal data structures.

Previously we tried to resolve the issue by clearing the `__ngContext__` when a node is removed
(see https://github.com/angular/angular/pull/36011), but we decided not to proceeed, because it can
slow down destruction due to a megamorphic write.

These changes aim to address the issue while reducing the performance impact by assigning a unique
ID when an `LView` is created and adding it to `__ngContext__`. All active views are tracked in
a map where their unique ID is used as the key. We don't need to worry about leaks within that map,
because `LView`s are an internal data structure and we have complete control over when they are
created and destroyed.

Fixes #41047.

PR Close #41358
2021-04-26 09:31:41 -07:00
..
2021-02-22 12:37:40 -08:00

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