# get-tsconfig [](https://npm.im/get-tsconfig) [](https://npm.im/esbuild-loader)
Find and parse `tsconfig.json` files.
### Features
- Zero dependency (not even TypeScript)
- Tested against TypeScript for correctness
- Supports comments & dangling commas in `tsconfig.json`
- Resolves [`extends`](https://www.typescriptlang.org/tsconfig/#extends)
- Fully typed `tsconfig.json`
- Validates and throws parsing errors
- Tiny! `7 kB` Minified + Gzipped
## Install
```bash
npm install get-tsconfig
```
## Why?
For TypeScript related tooling to correctly parse `tsconfig.json` file without depending on TypeScript.
## API
### getTsconfig(searchPath?, configName?, cache?)
Searches for a `tsconfig.json` file and parses it. Returns `null` if a config file cannot be found, or an object containing the path and parsed TSConfig object if found.
Returns:
```ts
type TsconfigResult = {
/**
* The path to the tsconfig.json file
*/
path: string
/**
* The resolved tsconfig.json file
*/
config: TsConfigJsonResolved
}
```
#### searchPath
Type: `string`
Default: `process.cwd()`
Accepts a path to a file or directory to search up for a `tsconfig.json` file.
#### configName
Type: `string`
Default: `tsconfig.json`
The file name of the TypeScript config file.
#### cache
Type: `Map`
Default: `new Map()`
Optional cache for fs operations.
#### Example
```ts
import { getTsconfig } from 'get-tsconfig'
// Searches for tsconfig.json starting in the current directory
console.log(getTsconfig())
// Find tsconfig.json from a TypeScript file path
console.log(getTsconfig('./path/to/index.ts'))
// Find tsconfig.json from a directory file path
console.log(getTsconfig('./path/to/directory'))
// Explicitly pass in tsconfig.json path
console.log(getTsconfig('./path/to/tsconfig.json'))
// Search for jsconfig.json - https://code.visualstudio.com/docs/languages/jsconfig
console.log(getTsconfig('.', 'jsconfig.json'))
```
---
### parseTsconfig(tsconfigPath, cache?)
The `tsconfig.json` parser used internally by `getTsconfig`. Returns the parsed tsconfig as `TsConfigJsonResolved`.
#### tsconfigPath
Type: `string`
Required path to the tsconfig file.
#### cache
Type: `Map`
Default: `new Map()`
Optional cache for fs operations.
#### Example
```ts
import { parseTsconfig } from 'get-tsconfig'
// Must pass in a path to an existing tsconfig.json file
console.log(parseTsconfig('./path/to/tsconfig.custom.json'))
```
---
---
### createFileMatcher(tsconfig: TsconfigResult, caseSensitivePaths?: boolean)
Given a `tsconfig.json` file, it returns a file-matcher function that determines whether it should apply to a file path.
```ts
type FileMatcher = (filePath: string) => TsconfigResult['config'] | undefined
```
#### tsconfig
Type: `TsconfigResult`
Pass in the return value from `getTsconfig`, or a `TsconfigResult` object.
#### caseSensitivePaths
Type: `boolean`
By default, it uses [`is-fs-case-sensitive`](https://github.com/privatenumber/is-fs-case-sensitive) to detect whether the file-system is case-sensitive.
Pass in `true` to make it case-sensitive.
#### Example
For example, if it's called with a `tsconfig.json` file that has `include`/`exclude`/`files` defined, the file-matcher will return the config for files that match `include`/`files`, and return `undefined` for files that don't match or match `exclude`.
```ts
const tsconfig = getTsconfig()
const fileMatcher = tsconfig && createFileMatcher(tsconfig)
/*
* Returns tsconfig.json if it matches the file,
* undefined if not
*/
const configForFile = fileMatcher?.('/path/to/file.ts')
const distCode = compileTypescript({
code: sourceCode,
tsconfig: configForFile
})
```
---
### createPathsMatcher(tsconfig: TsconfigResult)
Given a tsconfig with [`compilerOptions.paths`](https://www.typescriptlang.org/tsconfig#paths) defined, it returns a matcher function.
The matcher function accepts an [import specifier (the path to resolve)](https://nodejs.org/api/esm.html#terminology), checks it against `compilerOptions.paths`, and returns an array of possible paths to check:
```ts
function pathsMatcher(specifier: string): string[]
```
This function only returns possible paths and doesn't actually do any resolution. This helps increase compatibility wtih file/build systems which usually have their own resolvers.
#### Example
```ts
import { getTsconfig, createPathsMatcher } from 'get-tsconfig'
const tsconfig = getTsconfig()
const pathsMatcher = createPathsMatcher(tsconfig)
function exampleResolver(request: string) {
if (pathsMatcher) {
const tryPaths = pathsMatcher(request)
// Check if paths in `tryPaths` exist
}
}
```
## FAQ
### How can I use TypeScript to parse `tsconfig.json`?
This package is a re-implementation of TypeScript's `tsconfig.json` parser.
However, if you already have TypeScript as a dependency, you can simply use it's API:
```ts
import {
sys as tsSys,
findConfigFile,
readConfigFile,
parseJsonConfigFileContent
} from 'typescript'
// Find tsconfig.json file
const tsconfigPath = findConfigFile(process.cwd(), tsSys.fileExists, 'tsconfig.json')
// Read tsconfig.json file
const tsconfigFile = readConfigFile(tsconfigPath, tsSys.readFile)
// Resolve extends
const parsedTsconfig = parseJsonConfigFileContent(
tsconfigFile.config,
tsSys,
path.dirname(tsconfigPath)
)
```
## Sponsors
