feat: provide load and config API

Author: antongolub

src/main/ts/envapi.ts

@@ -1,3 +1,10 @@
+import fs from 'node:fs'
+import path from 'node:path'
+
+const Q1 = '"' // double quote
+const Q2 = "'" // single quote
+const Q3 = '`' // backtick
+
 export const parse = (content: string): NodeJS.ProcessEnv => {
   const kr = /^[a-zA-Z_]+\w*$/
   const sr = /\s/
@@ -37,7 +44,7 @@ export const parse = (content: string): NodeJS.ProcessEnv => {
       }
     }
 
-    if (c === '"' || c === "'" || c === '`') {
+    if (c === Q1 || c === Q2 || c === Q3) {
       if (!q && !b) {
         q = c
         continue
@@ -55,10 +62,6 @@ export const parse = (content: string): NodeJS.ProcessEnv => {
   return e
 }
 
-const Q1 = '"' // double quote
-const Q2 = "'" // single quote
-const Q3 = '`' // backtick
-
 const formatValue = (v: string): string => {
   const q1 = v.includes(Q1)
   const q2 = v.includes(Q2)
@@ -74,4 +77,23 @@ const formatValue = (v: string): string => {
 export const stringify = (env: NodeJS.ProcessEnv): string =>
   Object.entries(env).map(([k, v]) => `${k}=${formatValue(v || '')}`).join('\n')
 
-export default { parse, stringify }
+const _load = (
+  read: (file: string) => string,
+  ...files: string[]
+): NodeJS.ProcessEnv =>
+  files
+    .reverse()
+    .reduce((m, f) => Object.assign(m, parse(read(path.resolve(f)))), {})
+export const load = (...files: string[]): NodeJS.ProcessEnv =>
+  _load((file) => fs.readFileSync(file, 'utf8'), ...files)
+export const loadSafe = (...files: string[]): NodeJS.ProcessEnv =>
+  _load(
+    (file: string): string =>
+      fs.existsSync(file) ? fs.readFileSync(file, 'utf8') : '',
+    ...files
+  )
+
+export const config = (def = '.env', ...files: string[]): NodeJS.ProcessEnv =>
+  Object.assign(process.env, loadSafe(def, ...files))
+
+export default { parse, stringify, load, loadSafe, config }

src/test/ts/index.test.ts

@@ -1,9 +1,27 @@
 import * as assert from 'node:assert'
-import { describe, it } from 'vitest'
-import { parse, stringify } from '../../main/ts/index.js'
+import fs from 'node:fs'
+import os from 'node:os'
+import path from 'node:path'
+import { describe, test, afterAll } from 'vitest'
+import { parse, stringify, load, loadSafe, config } from '../../main/ts/index.js'
+
+const randomId= () => Math.random().toString(36).slice(2)
+const tempdir = (prefix: string = `temp-${randomId()}`): string => {
+  const dirpath = path.join(os.tmpdir(), prefix)
+  fs.mkdirSync(dirpath, { recursive: true })
+  return dirpath
+}
+const tempfile = (name?: string, data?: string | Buffer): string => {
+  const filepath = name
+    ? path.join(tempdir(), name)
+    : path.join(os.tmpdir(), `temp-${randomId()}`)
+  if (data === undefined) fs.closeSync(fs.openSync(filepath, 'w'))
+  else fs.writeFileSync(filepath, data)
+  return filepath
+}
 
 describe('parse/stringify', () => {
-  it('works', () => {
+  test('works', () => {
     const str = `SIMPLE=xyz123
 # comment ###
 NON_INTERPOLATED='raw text without variable interpolation' 
@@ -53,9 +71,59 @@ JSONSTR='{"foo": "b a r"}'`
 )
   })
 
-  it('throws on invalid input', () => {
+  test('throws on invalid input', () => {
     assert.throws(() => parse('BRO-KEN=xyz123'))
     assert.throws(() => parse('BRO KEN=xyz123'))
     assert.throws(() => parse('1BROKEN=xyz123'))
   })
+
+  describe('load()', () => {
+    const file1 = tempfile('.env.1', 'ENV1=value1\nENV2=value2')
+    const file2 = tempfile('.env.2', 'ENV2=value222\nENV3=value3')
+    afterAll(() => {
+      fs.unlinkSync(file1)
+      fs.unlinkSync(file2)
+    })
+
+    test('loads env from files', () => {
+      const env = load(file1, file2)
+      assert.equal(env.ENV1, 'value1')
+      assert.equal(env.ENV2, 'value2')
+      assert.equal(env.ENV3, 'value3')
+    })
+
+    test('throws error on ENOENT', () => {
+      try {
+        load('./.env')
+        throw new Error('shouldnt have thrown')
+      } catch (e: any) {
+        assert.equal(e.code, 'ENOENT')
+        assert.equal(e.errno, -2)
+      }
+    })
+  })
+
+  describe('loadSafe()', () => {
+    const file1 = tempfile('.env.1', 'ENV1=value1\nENV2=value2')
+    const file2 = '.env.notexists'
+
+    afterAll(() => fs.unlinkSync(file1))
+
+    test('loads env from files', () => {
+      const env = loadSafe(file1, file2)
+      assert.equal(env.ENV1, 'value1')
+      assert.equal(env.ENV2, 'value2')
+    })
+  })
+
+  describe('config()', () => {
+    test('updates process.env', () => {
+      const file1 = tempfile('.env.1', 'ENV1=value1')
+
+      assert.equal(process.env.ENV1, undefined)
+      config(file1)
+      assert.equal(process.env.ENV1, 'value1')
+      delete process.env.ENV1
+    })
+  })
 })