exception

exception holds the error classes the rest of the library throws. Nothing in it depends on the Apps Script runtime.

Packages

Package	Covers
`exception`	the base classes and the general-purpose exceptions
`exception/appsscript`	failures raised by the Sheets, Slides, and Admin SDK helpers
`exception/net`	authentication failures

The hierarchy, the catching patterns, and the table of which function throws which exception are in Exception handling. This page covers using the classes in your own code.

Extending the hierarchy

A script with its own failure modes can join the hierarchy rather than throwing bare Error objects. Extend RuntimeException for anything raised while the script runs:

import { RuntimeException } from "apps-script-utils";

export class QuotaExceededException extends RuntimeException {}

That is the whole class. Exception sets name from new.target, so the subclass reports its own name with no constructor of its own:

const error = new QuotaExceededException("daily email quota reached");

error.name; // "QuotaExceededException"
error.getMessage(); // "daily email quota reached"
Object.prototype.toString.call(error); // "[object QuotaExceededException]"

It also inherits the behaviour that matters at the catch site — Exception.isException() recognises it, and instanceof RuntimeException holds.

Wrapping a caught error

Every constructor accepts an existing Error and reuses its message, which keeps the original text while changing the type:

import { RuntimeException } from "apps-script-utils";

try {
  UrlFetchApp.fetch(endpoint);
} catch (error) {
  throw new RuntimeException(error);
}

Choosing a class

Prefer an existing class where one fits — a caller that already handles IllegalArgumentException will handle yours:

Situation	Class
An argument is the wrong type or out of range	`IllegalArgumentException`
A required value was `null` or `undefined`	`NullPointerException`
A string argument was empty	`EmptyStringException`
A credential was missing or rejected	`AuthenticationException`
A dependency was never configured	`ServiceIsNotDefinedException`, `RepositoryIsNotDefinedException`

Full list

Exceptions lists every class with a link to its source.

23 September 2026

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