[fix] Modal: close only one modal per Escape key press

[vmanapat]

When one dialog is open on top of another, pressing Escape once closes both instead of just the top one.

Test case: https://codesandbox.io/s/t85xr3 (Open settings, then Delete deck, then press Escape once. Both modals close.)

Change

A modal now closes on Escape keyup only when the same key press began while it was the active modal and its keydown was not handled (defaultPrevented). The keydown is recorded in the capture phase, so it is still seen when a focused TextInput stops its propagation. Closing stays on keyup, so:

• Escape from a focused TextInput still closes the modal
• holding Escape closes one modal, not one per key repeat
• a key press that began before the modal became active does not close it

Tests

The existing Escape tests now send keydown followed by keyup, as a real key press does. New tests cover stacked modals with and without the app handling Escape, a focused TextInput, holding Escape, a handled keydown, and a key press that began before the modal was active.

npm run format, npm run lint and npm run unit pass. npm run flow reports no new errors.

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit 95e2d84:

Sandbox	Source
react-native-web-examples	Configuration
rnw-modal-escape	PR