Importing & exporting

To build composable programs, it is necessary to be able to import and export functions from other modules. This is accomplished by using ECMA script modules in Deno.

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To export a function, you use the export keyword.

./util.ts

export function sayHello(thing: string) {
  console.log(`Hello, ${thing}!`);
}

You can also export types, variables, and classes.

./util.ts

export interface Foo {}
export class Bar {}
export const baz = "baz";

To import things from files other files can use the import keyword.

./main.ts

import { sayHello } from "./util.ts";
sayHello("World");

You can also import all exports from a file.

./main.ts

import * as util from "./util.ts";
util.sayHello("World");

Imports don't have to be relative, they can also reference absolute file, https, or [JSR](https://jsr.io) URLs.

./main.ts

import { camelCase } from "jsr:@luca/cases@1";
console.log(camelCase("hello world")); // helloWorld

import OpenAI from "https://deno.land/x/openai@v4.53.0/mod.ts";
const client = new OpenAI();

Importing & exporting

Additional resources