# auto-config-loader
> Find and load configuration from a package.json property, rc file, or CommonJS module.
Latest version **3.0.4** (published 2026-03-19) · MIT license · 0 weekly downloads
## Install
```sh
npm install auto-config-loader
pnpm add auto-config-loader
yarn add auto-config-loader
bun add auto-config-loader
```
## Health
**Score 60/100 (C)** — status: active.
Positive: has types; esm support; no vulnerabilities; has provenance.
Warnings: low downloads.
## Facts
| | |
|---|---|
| Version | 3.0.4 |
| Published | 2026-03-19 |
| First published | 2023-06-01 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Node | ^20.17.0 \|\| >=22.9.0 |
| Dependencies | 7 |
| Unpacked size | 42 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| GitHub stars | 7 |
| Author | jaywcjlove |
| Maintainers | wcjiang |
| Keywords | rc, config, loader, load, configuration, cjs, commonjs, esm, es module, yml-config, js-config, ts-config, toml-config, yml, js, ts, toml, typescript, config-loader, auto-config-loader |
## Links
- npm: https://www.npmjs.com/package/auto-config-loader
- Repository: https://github.com/jaywcjlove/auto-config-loader
- Homepage: https://jaywcjlove.github.io/auto-config-loader
- Issues: https://github.com/jaywcjlove/auto-config-loader/issues
- Funding: https://jaywcjlove.github.io/#/sponsor
- npm.io page: https://npm.io/package/auto-config-loader
## Dependencies (7)
- [ini](https://npm.io/package/ini.md) ^6.0.0
- [jiti](https://npm.io/package/jiti.md) ^2.6.1
- [sucrase](https://npm.io/package/sucrase.md) ^3.35.1
- [lodash.merge](https://npm.io/package/lodash.merge.md) ^4.6.2
- [toml-eslint-parser](https://npm.io/package/toml-eslint-parser.md) ^0.10.0
- [yaml-eslint-parser](https://npm.io/package/yaml-eslint-parser.md) ^1.3.0
- [jsonc-eslint-parser](https://npm.io/package/jsonc-eslint-parser.md) ^2.4.1
## Alternatives
- [@mapbox/jsonlint-lines-primitives](https://npm.io/package/@mapbox/jsonlint-lines-primitives.md) — 5.3M weekly downloads
- [reftools](https://npm.io/package/reftools.md) — 3.5M weekly downloads
- [@hey-api/openapi-ts](https://npm.io/package/@hey-api/openapi-ts.md) — 3.5M weekly downloads
- [@mapbox/geojson-rewind](https://npm.io/package/@mapbox/geojson-rewind.md) — 2.4M weekly downloads
- [turbo-stream](https://npm.io/package/turbo-stream.md) — 1.7M weekly downloads
## Recent versions
- 3.0.4 (latest) — 2026-03-19
- 3.0.3 — 2025-11-20
- 3.0.2 — 2025-11-20
- 3.0.1 — 2025-11-03
- 3.0.0 — 2025-08-28
- 2.0.2 — 2024-12-11
- 2.0.1 — 2024-12-11
- 2.0.0 — 2024-12-11
- 1.7.8 — 2024-11-21
- 1.7.7 — 2024-03-16
- 1.7.6 — 2023-11-27
- 1.7.5 — 2023-11-08
- 1.7.4 — 2023-06-10
- 1.7.3 — 2023-06-10
- 1.7.2 — 2023-06-10
- … 23 more at https://npm.io/package/auto-config-loader/versions
## README
Auto Config Loader
===
[](https://jaywcjlove.github.io/#/sponsor)
[](https://x.com/jaywcjlove)
[](https://github.com/jaywcjlove/auto-config-loader/actions/workflows/main.yml)
[](https://npmjs.org/package/auto-config-loader)
[](https://jaywcjlove.github.io/auto-config-loader/lcov-report/)
[](https://www.npmjs.com/package/auto-config-loader)
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.
[V1 To V2 Migration](#v1-to-v2-migration)
## Features
- Support [JSON](https://www.json.org), [JSONC](https://github.com/microsoft/node-jsonc-parser), [JSON5](https://json5.org/), [YAML](https://yaml.org/), [TOML](https://toml.io), [INI](https://en.wikipedia.org/wiki/INI_file), [CJS](http://www.commonjs.org), [Typescript](https://www.typescriptlang.org/), and ESM config load.
- Reads config from the nearest `package.json` file
## Install
```bash
$ npm i auto-config-loader
```
## Quick start
```js
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 = await autoConf('namespace', {
default: {
testItem2: 'some value'
}
});
```
## Load JS
Load the JS file and return the result, support `.js`, `.cjs`, `.mjs`, `.ts`.
```js
// => ./app/app.config.js
export default {
name: 'app'
}
```
```ts
import { loadConf } from 'auto-config-loader/load-conf';
interface Config {
name: string;
}
const result = await loadConf('./app/app.config.js');
// => { name: 'app' }
```
## Option
```ts
import { LoadConfOption } from 'auto-config-loader';
export type LoaderFunc = (filepath: string, content: string, jsOption?: LoadConfOption) => T | Promise;
export type Loader = Record>;
export interface AutoConfOption {
searchPlaces?: string[];
/** An object that maps extensions to the loader functions responsible for loading and parsing files with those extensions. */
loaders?: Loader;
/** Specify default configuration. It has the lowest priority and is applied after extending config. */
default?: 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;
}
export declare const getConfigPath: () => string;
/**
* 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 declare function autoConf(namespace?: string, option?: AutoConfOption): Promise<{} & T>;
export default autoConf;
```
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 `${moduleName}` represents the name of the tool:
**Default `searchPlaces`:**
```js
[
'package.json',
`.${moduleName}rc`,
`.${moduleName}rc.json`,
`.${moduleName}rc.json5`,
`.${moduleName}rc.jsonc`,
`.${moduleName}rc.yaml`,
`.${moduleName}rc.yml`,
`.${moduleName}rc.toml`,
`.${moduleName}rc.ini`,
`.${moduleName}rc.js`,
`.${moduleName}rc.ts`,
`.${moduleName}rc.cjs`,
`.${moduleName}rc.mjs`,
`.config/${moduleName}rc`,
`.config/${moduleName}rc.json`,
`.config/${moduleName}rc.json5`,
`.config/${moduleName}rc.jsonc`,
`.config/${moduleName}rc.yaml`,
`.config/${moduleName}rc.yml`,
`.config/${moduleName}rc.toml`,
`.config/${moduleName}rc.ini`,
`.config/${moduleName}rc.js`,
`.config/${moduleName}rc.ts`,
`.config/${moduleName}rc.cjs`,
`.config/${moduleName}rc.mjs`,
`${moduleName}.config.js`,
`${moduleName}.config.ts`,
`${moduleName}.config.cjs`,
`${moduleName}.config.mjs`,
]
```
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`:
```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:
```js
{
"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.
## Loader
### `.js`,`.ts`,`.cjs`,`.mjs`
```ts
import type jiti from 'jiti';
import { Options } from 'sucrase';
type Jiti = ReturnType;
type JITIOptions = Jiti['options'];
export interface LoadConfOption {
jiti?: boolean;
jitiOptions?: JITIOptions;
transformOption?: Options;
}
export declare function loadConf(path: string, option?: LoadConfOption): Promise;
export declare function jsLoader(
filepath: string,
content: string,
option?: LoadConfOption
): Promise;
```
Modify default `.js`,`.ts`,`.cjs`,`.mjs` loader parameters.
```js
import load, { jsLoader } from 'auto-config-loader';
function loadJS(filepath, content) {
return jsLoader(filepath, content, {
// change option...
});
}
const data = await load('namespace', {
loaders: {
'.js': loadJS,
'.ts': loadJS,
'.cjs': loadJS,
'.mjs': loadJS,
},
default: {
testItem2: 'some value'
}
});
```
example:
```ts
import { jsLoader } from 'auto-config-loader';
const data = jsLoader('/path/to/file/name.js')
```
### `.ini`
```ts
export declare function iniLoader(_: string, content: string): T;
```
example:
```ts
import { iniLoader } from 'auto-config-loader';
const data = iniLoader(undefined, `...`)
```
### `.json`,`.jsonc`, `json5`
```ts
export declare function jsonLoader(_: string, content: string): T;
```
example:
```ts
import { jsonLoader } from 'auto-config-loader';
const data = jsonLoader(undefined, `{ "a": 123 }`)
```
### `.toml`
```ts
export declare function tomlLoader(_: string, content: string): T;
```
example:
```ts
import { tomlLoader } from 'auto-config-loader';
const data = tomlLoader(undefined, `...`)
```
### `.yaml`
```ts
export declare function yamlLoader(_: string, content: string): T;
```
example:
```ts
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.
```js
import load from 'auto-config-loader';
import yaml from 'yaml';
function loadYaml(filepath, content) {
return yaml.parse(content);
}
const data = await load('namespace', {
searchPlaces: [
'.namespacerc.yaml',
'.namespacerc.yml',
],
loaders: {
'.yaml': loadYaml,
'.yml': loadYaml,
},
default: {
testItem2: 'some value'
}
});
```
## Utils
### merge
```ts
export declare const merge: {
(object: TObject, source: TSource): TObject & TSource;
(object: TObject, source1: TSource1, source2: TSource2): TObject & TSource1 & TSource2;
(object: TObject, source1: TSource1, source2: TSource2, source3: TSource3): TObject & TSource1 & TSource2 & TSource3;
(object: TObject, source1: TSource1, source2: TSource2, source3: TSource3, source4: TSource4): TObject & TSource1 & TSource2 & TSource3 & TSource4;
(object: any, ...otherArgs: any[]): any;
};
```
### findConfigFile
```ts
export declare function findConfigFile(
moduleName: string,
root: string,
searchPlaces?: string[]
): string;
```
### getConfigPath
```ts
export declare const getConfigPath: () => string;
```
Example:
```ts
import { autoConf, getConfigPath } from 'auto-config-loader';
const data = autoConf('idoc');
const configPath = getConfigPath();
// => /.autoconfrc.js
```
## V1 To V2 Migration
This guide provides the steps to migrate to the latest version of the configuration loader API.
### Key Changes
1. **Loader Functions Support Async**
- `LoaderFunc` now supports returning `T` or `Promise`.
- Update custom loaders to handle asynchronous operations if needed.
**Example:**
```ts
export type LoaderFunc = (
filepath: string,
content: string,
jsOption?: LoadConfOption
) => T | Promise;
```
2. **`autoConf` Returns a Promise**
- The `autoConf` function now returns a `Promise` instead of a synchronous result.
- Update your code to handle asynchronous calls.
**Example:**
```ts
export declare function autoConf(
namespace?: string,
option?: AutoConfOption
): Promise<{} & T>;
```
### Migration Steps
#### 1. Update Custom Loader Functions
If you have custom loaders, update their return types to support asynchronous operations:
**Example:**
```ts
const jsonLoader: LoaderFunc = async (
filepath, content
) => JSON.parse(content);
```
#### 2. Handle Asynchronous `autoConf` Calls
Update all calls to `autoConf` to use `await` or `.then` to handle Promises:
**Example Using `await`:**
```ts
const config = await autoConf('myNamespace', options);
console.log(config);
```
**Example Using `.then`:**
```ts
autoConf('myNamespace', options).then(config => {
console.log(config);
});
```
## Related
- [cosmiconfig](https://github.com/cosmiconfig/cosmiconfig) Find and load configuration from a package.json property, rc file, or CommonJS module
- [cjson](https://www.npmjs.com/package/cjson) Comments enabled json loader (Commented JavaScript Object Notation)
- [Config Loader](https://www.npmjs.com/package/@web/config-loader) Load user config files for node js projects.
- [Lilconfig](https://www.npmjs.com/package/lilconfig) Zero-dependency nodejs config seeker.
- [proload](https://github.com/natemoo-re/proload) Searches for and loads your tool's JavaScript configuration files with full support for CJS, ESM, TypeScript and more.
- [rc](https://github.com/dominictarr/rc) The non-configurable configuration loader for lazy people.
Library | Last commit | Download | loaders | config ext
:-- | --- | --- | --- | ---
**auto-config-loader** | [](https://github.com/jaywcjlove/auto-config-loader/commits) | [](https://www.npmjs.com/package/auto-config-loader) | ✅ | `.js`, `.ts`, `.cjs`, `.mjs`, `.json`, `.jsonc`, `json5`, `.ini`, `.toml`, `.yaml` ++
cosmiconfig | [](https://github.com/cosmiconfig/cosmiconfig/commits) | [](https://www.npmjs.com/package/cosmiconfig) | ✅ | `.json`, `.yaml`, `.yml`, `.js`, `.mjs`, `.cjs`
~~rc~~ | [](https://github.com/dominictarr/rc/commits) | [](https://www.npmjs.com/package/rc) | ✅ | `.json`, `.yaml`, `.yml`, `.js`, `.mjs`, `.cjs`
@proload/core | [](https://github.com/natemoo-re/proload/commits) | [](https://www.npmjs.com/package/@proload/core) | ✅ | `.js`, `.ts`, `.cjs`, `.mjs`, `.json`, `.jsonc`, `json5`, `.ini`, `.toml`, `.yaml` ++
lilconfig | [](https://github.com/antonk52/lilconfig/commits) | [](https://www.npmjs.com/package/lilconfig) | ✅ | `.js`, `.cjs`, `.mjs`, `.json` ++
~~cjson~~ | [](https://github.com/kof/node-cjson/commits) | [](https://www.npmjs.com/package/cjson) | ✅ | `.json`
@web/config-loader | [](https://github.com/modernweb-dev/web/commits) | [](https://www.npmjs.com/package/@web/config-loader) | ❌ | `.js`, `.mjs`, `.cjs`
## Contributors
As always, thanks to our amazing contributors!
Made with [contributors](https://github.com/jaywcjlove/github-action-contributors).
## License
This package is licensed under the MIT License.
---
_Source: https://npm.io/package/auto-config-loader · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._
