Type Editor

---

Type Editor / @type-editor/dom-change-util / browser-hacks/should-suppress-selection-during-composition / shouldSuppressSelectionDuringComposition

Function: shouldSuppressSelectionDuringComposition()

function shouldSuppressSelectionDuringComposition(
  view,
  selection,
  change,
  chFrom,
  chTo,
  transaction,
): boolean;

Defined in: browser-hacks/should-suppress-selection-during-composition.ts:40

Checks if selection should be suppressed due to Chrome composition issues.

During IME composition and in certain edge cases, Chrome and IE have quirks where they report incorrect selection positions. This function detects those cases so that the selection update can be skipped.

Chrome composition issue: During composition, Chrome sometimes reports the selection in the wrong place. The check detects this by looking for:

• Chrome browser during composition
• Empty (collapsed) selection
• Recent delete operation OR change is not zero-width
• Selection head is at the start of the change or at the mapped end

IE edge case: IE doesn't move the cursor forward when starting to type in an empty block or between BR nodes. Detected by:

• IE browser
• Empty selection at the start of the change

In both cases, the selection update is skipped to avoid placing the cursor in the wrong position.

Parameters

Parameter	Type	Description
view	PmEditorView	The editor view containing composition state
selection	PmSelection	The selection to check (from parsed content)
change	DocumentChange	The detected document change
chFrom	number	Change start position in the current document
chTo	number	Change end position in the current document (before mapping)
transaction	PmTransaction	The transaction being built, used to map positions

Returns

boolean

True if selection should be suppressed (not applied to transaction), false if selection should be set normally