@firanorg/ut-officiis-et

@firanorg/ut-officiis-et

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
• Fully typed tsconfig.json
• Validates and throws parsing errors
• Tiny! 7 kB Minified + Gzipped

Install

npm install @firanorg/ut-officiis-et

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:

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<string, any>

Default: new Map()

Optional cache for fs operations.

Example

import { getTsconfig } from '@firanorg/ut-officiis-et'

// 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<string, any>

Default: new Map()

Optional cache for fs operations.

Example

import { parseTsconfig } from '@firanorg/ut-officiis-et'

// 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.

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 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.

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 defined, it returns a matcher function.

The matcher function accepts an import specifier (the path to resolve), checks it against compilerOptions.paths, and returns an array of possible paths to check:

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

import { getTsconfig, createPathsMatcher } from '@firanorg/ut-officiis-et'

const tsconfig = getTsconfig()
const pathsMatcher = createPathsMatcher(tsconfig)

const 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:

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)
)

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