Auto Config Loader

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Find and load configuration from a package.json property, rc file, or CommonJS module. It has smart default based on traditional expectations in the JavaScript ecosystem. But it's also flexible enough to search anywhere you want and load whatever you want.



$ npm i auto-config-loader

Quick start

const autoConf = require('auto-config-loader');

import { autoConf } from 'auto-config-loader';

// will look for:
// process.cwd() + '.namespacerc'
// process.cwd() + '.namespacerc.js'
// process.cwd() + '.namespacerc.ts'
// process.cwd() + '.namespacerc.mjs'
// process.cwd() + '.namespacerc.cjs'
// process.cwd() + '.namespacerc.json'
// process.cwd() + '.namespacerc.json5'
// process.cwd() + '.namespacerc.jsonc'
// process.cwd() + '.namespacerc.yaml'
// process.cwd() + '.namespacerc.yml'
// process.cwd() + '.namespacerc.toml'
// process.cwd() + 'namespace.config.mjs'
// process.cwd() + 'namespace.config.cjs'
// process.cwd() + 'namespace.config.js'
// ........
const data = autoConf('namespace', {
  default: {
    testItem2: 'some value'

Load JS

Load the JS file and return the result, support .js, .cjs, .mjs, .ts.

// => ./app/app.config.js
export default {
  name: 'app'
import { loadConf } from 'auto-config-loader/load-conf';

interface Config {
  name: string;

const result = loadConf<Config>('./app/app.config.js');
// => { name: 'app' }


import { LoadConfOption } from 'auto-config-loader';
export type LoaderFunc<T> = (filepath: string, content: string, jsOption?: LoadConfOption) => T;
export type Loader<T> = Record<string, LoaderFunc<T>>;
export interface AutoConfOption<T> {
  searchPlaces?: string[];
  /** An object that maps extensions to the loader functions responsible for loading and parsing files with those extensions. */
  loaders?: Loader<T>;
  /** Specify default configuration. It has the lowest priority and is applied after extending config. */
  defaluts?: T;
  /** Resolve configuration from this working directory. The default is `process.cwd()` */
  cwd?: string;
  /** Default transform js configuration */
  jsOption?: LoadConfOption;
  /** @deprecated use `mustExist` instead */
  ignoreLog?: boolean;
  mustExist?: boolean;
 * Find and load configuration from a `package.json` property, `rc` file, or `CommonJS` module.
 * @param namespace {string} Configuration base name. The default is `autoconf`.
 * @param option 
export default function autoConf<T>(namespace?: string, option?: AutoConfOption<T>): {} & T;

Discover configurations in the specified directory order. When configuring a tool, you can use multiple file formats and put these in multiple places. Usually, a tool would mention this in its own README file, but by default, these are the following places, where ${moduleName} represents the name of the tool:

Default searchPlaces:


Configurations are loaded sequentially, and the configuration file search is terminated when a configuration file exists.

The content of these files is defined by the tool. For example, you can add a semi configuration value to false using a file called .config/autoconfig.yml:

semi: true

Additionally, you have the option to put a property named after the tool in your package.json file, with the contents of that property being the same as the file contents. To use the same example as above:

  "name": "your-project",
  "autoconfig": {
    "semi": true

This has the advantage that you can put the configuration of all tools (at least the ones that use auto-config-loader) in one file.



import type { JITIOptions } from 'jiti/dist/types';
import { Options } from 'sucrase';
export interface LoadConfOption {
  jiti?: boolean;
  jitiOptions?: JITIOptions;
  transformOption?: Options;
export declare function loadConf<T>(path: string, option?: LoadConfOption): T;
export declare function jsLoader<T>(filepath: string, content: string, option?: LoadConfOption): T;

Modify default .js,.ts,.cjs,.mjs loader parameters.

import load, { jsLoader } from 'auto-config-loader';

function loadJS(filepath, content) {
  return jsLoader(filepath, content, {
    // change option...

const data = load('namespace', {
  loaders: {
    '.js': loadJS,
    '.ts': loadJS,
    '.cjs': loadJS,
    '.mjs': loadJS,
  default: {
    testItem2: 'some value'


import { jsLoader } from 'auto-config-loader';

const data = jsLoader('/path/to/file/name.js')


export declare function iniLoader<T>(_: string, content: string): T;


import { iniLoader } from 'auto-config-loader';

const data = iniLoader(undefined, `...`)

.json,.jsonc, json5

export declare function jsonLoader<T>(_: string, content: string): T;


import { jsonLoader } from 'auto-config-loader';

const data = jsonLoader(undefined, `{ "a": 123 }`)


export declare function tomlLoader<T>(_: string, content: string): T;


import { tomlLoader } from 'auto-config-loader';

const data = tomlLoader(undefined, `...`)


export declare function yamlLoader<T>(_: string, content: string): T;


import { yamlLoader } from 'auto-config-loader';

const data = yamlLoader(undefined, `...`)

Custom Yaml loader

This is an example, the default yaml/yml does not require a loader.

import load from 'auto-config-loader';
import yaml from 'yaml';

function loadYaml(filepath, content) {
  return yaml.parse(content);

const data = load('namespace', {
  searchPlaces: [
  loaders: {
    '.yaml': loadYaml,
    '.yml': loadYaml,
  default: {
    testItem2: 'some value'



export declare const merge: {
  <TObject, TSource>(object: TObject, source: TSource): TObject & TSource;
  <TObject_1, TSource1, TSource2>(object: TObject_1, source1: TSource1, source2: TSource2): TObject_1 & TSource1 & TSource2;
  <TObject_2, TSource1_1, TSource2_1, TSource3>(object: TObject_2, source1: TSource1_1, source2: TSource2_1, source3: TSource3): TObject_2 & TSource1_1 & TSource2_1 & TSource3;
  <TObject_3, TSource1_2, TSource2_2, TSource3_1, TSource4>(object: TObject_3, source1: TSource1_2, source2: TSource2_2, source3: TSource3_1, source4: TSource4): TObject_3 & TSource1_2 & TSource2_2 & TSource3_1 & TSource4;
  (object: any, ...otherArgs: any[]): any;


export declare function findConfigFile(moduleName: string, root: string, searchPlaces?: string[]): string;


export declare const getConfigPath: () => string;


import { autoConf, getConfigPath } from 'auto-config-loader';

const data = autoConf<Config>('idoc');
const configPath = getConfigPath();
// => /.autoconfrc.js
Library Last commit Download loaders config ext
auto-config-loader GitHub last commit NPM Downloads .js, .ts, .cjs, .mjs, .json, .jsonc, json5, .ini, .toml, .yaml ++
cosmiconfig GitHub last commit NPM Downloads .json, .yaml, .yml, .js, .mjs, .cjs
rc GitHub last commit NPM Downloads .json, .yaml, .yml, .js, .mjs, .cjs
@proload/core GitHub last commit NPM Downloads .js, .ts, .cjs, .mjs, .json, .jsonc, json5, .ini, .toml, .yaml ++
lilconfig GitHub last commit NPM Downloads .js, .cjs, .mjs, .json ++
cjson GitHub last commit NPM Downloads .json
@web/config-loader GitHub last commit NPM Downloads .js, .mjs, .cjs


As always, thanks to our amazing contributors!

Made with contributors.


This package is licensed under the MIT License.