angular-docs-cn/packages/core/schematics/migrations/template-var-assignment
Joey Perrott d1ea1f4c7f build: update license headers to reference Google LLC (#37205)
Update the license headers throughout the repository to reference Google LLC
rather than Google Inc, for the required license headers.

PR Close #37205
2020-05-26 14:26:58 -04:00
..
angular build: update license headers to reference Google LLC (#37205) 2020-05-26 14:26:58 -04:00
BUILD.bazel refactor(core): move google3 migration rules into single directory (#30956) 2019-07-23 15:52:40 -07:00
README.md
analyze_template.ts build: update license headers to reference Google LLC (#37205) 2020-05-26 14:26:58 -04:00
index.ts build: update license headers to reference Google LLC (#37205) 2020-05-26 14:26:58 -04:00

README.md

Assignments to template variables

With Ivy, assignments to template variables are no longer supported as template variables are effectively constants.

This means that assignments to template variables will break your application once Ivy is enabled by default. For example:

<button *ngFor="let option of options"
       (click)="option = 'newButtonText'">
  {{ option }}
</button>

In the example from above, a value is assigned to the option template variable on click. This will ultimately break your application and therefore the logic needs to be adjusted to not update the option variable, but rather the given element in the options array:

<button *ngFor="let option of options; let idx = index"
       (click)="options[idx] = 'newButtonText'">
  {{ option }}
</button>