isTextStyle
function isTextStyle(value: unknown): value is GoogleAppsScript.Spreadsheet.TextStyle;
An Apps Script service object has no constructor a script can test against, so the guard reads the tag the object reports for itself: value.toString() === "TextStyle". A plain object that reports the same tag passes too, which in practice means a test double.
isX and nonX answer a question and never interrupt control flow; requireX and requireNonX hand the value back or throw. The scheme is explained in Validation conventions.
Parameters
Parameter | Type | Description |
|---|---|---|
|
| The value to check. |
Returns
boolean — true when the value is a text style; otherwise false.
In TypeScript the guard narrows value to GoogleAppsScript.Spreadsheet.TextStyle inside the branch.
Examples
What passes and what does not
const style = SpreadsheetApp.newTextStyle().setBold(true).build();
isTextStyle(style); // => true
isTextStyle({}); // => false
isTextStyle(null); // => false
See also
Source
23 September 2026
This documentation was generated with AI (Claude) from the library's source code.