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Version: 2.1.0


The Dictionary constructor lets you access a specific Fastly Edge Dictionary.

Note: Can only be used when processing requests, not during build-time initialization.


new Dictionary(name);

Note: Dictionary() can only be constructed with new. Attempting to call it without new throws a TypeError.


Return value

A new Dictionary object.


  • TypeError
    • Thrown if no Dictionary exists with the provided name
    • Thrown if the provided name is longer than 255 in length
    • Thrown if the provided name is an empty string
    • Thrown if the provided name does not start with an ascii alphabetical character
    • Thrown if the provided name does not contain only ascii alphanumeric, underscore, and whitespace characters


In this example we have an Edge Dictionary named "animals" and we return the "cat" entry as the response body to the client.

/// <reference types="@fastly/js-compute" />
import { Dictionary } from "fastly:dictionary";
async function app (event) {
const config = new Dictionary('animals');
return new Response(config.get('cat'));
addEventListener("fetch", event => event.respondWith(app(event)));