nonTextOutput

function nonTextOutput<T>(value: T | TextOutput): value is T;

nonTextOutput(value) is the same test as !isTextOutput(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 — getMimeType, getContent. 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 \\| TextOutput`	The value to check.

Returns

boolean — true when the value is not a TextOutput; otherwise false.

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

Examples

What passes and what does not

const output = ContentService.createTextOutput("hi");

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

Source

src/appsscript/ui/nonTextOutput.ts

23 September 2026

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

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