nonHtmlOutput

function nonHtmlOutput<T>(value: T | HtmlOutput): value is T;

nonHtmlOutput(value) is the same test as !isHtmlOutput(value), written so that a guard clause reads as a sentence rather than as a negation.

An Apps Script service object has no constructor a script can test against, so the guard looks for the methods that define the type — getContent, setTitle, setXFrameOptionsMode. A stub that implements them passes, which is what makes code using this guard testable outside the runtime.

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
`value`	`T \\| HtmlOutput`	The value to check.

Returns

boolean — true when the value is not an HtmlOutput; otherwise false.

In TypeScript the guard narrows value to T inside the branch.

Examples

What passes and what does not

const output = HtmlService.createHtmlOutput("<p>hi</p>");

nonHtmlOutput({}); // => true
nonHtmlOutput(null); // => true
nonHtmlOutput(output); // => false

Source

src/appsscript/ui/nonHtmlOutput.ts

23 September 2026

This documentation was generated with AI (Claude) from the library's source code.

apps-script-utils 2.1.1 Help