Import a YAML file

Bun natively supports .yaml and .yml imports.

yaml

database:
  host: localhost
  port: 5432
  name: myapp

server:
  port: 3000
  timeout: 30

features:
  auth: true
  rateLimit: true

Import the file like any other source file.

import config from "./config.yaml";

config.database.host; // => "localhost"
config.server.port; // => 3000
config.features.auth; // => true

You can also use named imports to destructure top-level properties:

import { database, server, features } from "./config.yaml";

console.log(database.name); // => "myapp"
console.log(server.timeout); // => 30
console.log(features.rateLimit); // => true

Bun also supports Import Attributes syntax:

import config from "./config.yaml" with { type: "yaml" };

config.database.port; // => 5432

For parsing YAML strings at runtime, use Bun.YAML.parse():

const yamlString = `
name: John Doe
age: 30
hobbies:
  - reading
  - coding
`;

const data = Bun.YAML.parse(yamlString);
console.log(data.name); // => "John Doe"
console.log(data.hobbies); // => ["reading", "coding"]

TypeScript Support

To add TypeScript support for your YAML imports, create a declaration file with .d.ts appended to the YAML filename (e.g., config.yaml → config.yaml.d.ts);

const contents: {
  database: {
    host: string;
    port: number;
    name: string;
  };
  server: {
    port: number;
    timeout: number;
  };
  features: {
    auth: boolean;
    rateLimit: boolean;
  };
};

export = contents;

See Docs > API > YAML for complete documentation on YAML support in Bun.