chore: don't convert strings to numbers/booleans in the API

src/env-cmd.ts

@@ -56,7 +56,7 @@ export async function EnvCmd(
   const proc = spawn(command, commandArgs, {
     stdio: 'inherit',
     shell: options.useShell,
-    env: env as Record<string, string>,
+    env,
   })
 
   // Handle any termination signals for parent and child proceses

src/parse-env-file.ts

@@ -17,16 +17,16 @@ export async function getEnvFileVars(envFilePath: string): Promise<Environment>
 
   // Get the file extension
   const ext = extname(absolutePath).toLowerCase()
-  let env: Environment = {}
+  let env: unknown;
   if (IMPORT_HOOK_EXTENSIONS.includes(ext)) {
     // For some reason in ES Modules, only JSON file types need to be specifically delinated when importing them
     let attributeTypes = {}
     if (ext === '.json') {
       attributeTypes = { [importAttributesKeyword]: { type: 'json' } }
     }
-    const res = await import(pathToFileURL(absolutePath).href, attributeTypes) as Environment | { default: Environment }
-    if ('default' in res) {
-      env = res.default as Environment
+    const res: unknown = await import(pathToFileURL(absolutePath).href, attributeTypes)
+    if (typeof res === 'object' && res && 'default' in res) {
+      env = res.default
     } else {
       env = res
     }
@@ -35,7 +35,7 @@ export async function getEnvFileVars(envFilePath: string): Promise<Environment>
       env = await env
     }
 
-    return env;
+    return normalizeEnvObject(env, absolutePath)
   }
 
   const file = readFileSync(absolutePath, { encoding: 'utf8' })
@@ -83,22 +83,10 @@ export function parseEnvVars(envString: string): Environment {
       // inline comments.
       value = value.split('#')[0].trim();
     }
-  
+
     value = value.replace(/\\n/g, '\n');
 
-    // Convert string to JS type if appropriate
-    if (value !== '' && !isNaN(+value)) {
-      matches[key] = +value
-    }
-    else if (value === 'true') {
-      matches[key] = true
-    }
-    else if (value === 'false') {
-      matches[key] = false
-    }
-    else {
-      matches[key] = value
-    }
+    matches[key] = value
   }
   return JSON.parse(JSON.stringify(matches)) as Environment
 }
@@ -118,3 +106,27 @@ export function stripEmptyLines(envString: string): string {
   const emptyLinesRegex = /(^\n)/gim
   return envString.replace(emptyLinesRegex, '')
 }
+
+/**
+ * If we load data from a file like .js, the user
+ * might export something which is not an object.
+ *
+ * This function ensures that the input is valid,
+ * and converts the object's values to strings, for
+ * consistincy. See issue #125 for details.
+ */
+export function normalizeEnvObject(input: unknown, absolutePath: string): Environment {
+  if (typeof input !== 'object' || !input) {
+    throw new Error(`env-cmd cannot load “${absolutePath}” because it does not export an object.`)
+  }
+
+  const env: Environment = {};
+  for (const [key, value] of Object.entries(input)) {
+    // we're intentionally stringifying the value here, to
+    // match what `child_process.spawn` does when loading 
+    // env variables.
+    // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
+    env[key] = `${value}`
+  }
+  return env
+}

src/types.ts

@@ -1,7 +1,7 @@
 import type { Command } from '@commander-js/extra-typings'
 
 // Define an export type
-export type Environment = Partial<Record<string, string | number | boolean>>
+export type Environment = Partial<Record<string, string>>
 
 export type RCEnvironment = Partial<Record<string, Environment>>
 

test/parse-env-file.spec.ts

@@ -29,8 +29,8 @@ describe('parseEnvVars', (): void => {
     assert(envVars.BOB === 'COOL')
     assert(envVars.NODE_ENV === 'dev')
     assert(envVars.ANSWER === '42 AND COUNTING')
-    assert(envVars.NUMBER === 42)
-    assert(envVars.BOOLEAN === true)
+    assert(envVars.NUMBER === '42')
+    assert(envVars.BOOLEAN === 'true')
   })
 
   it('should parse out all env vars in string with format \'key=value\'', (): void => {
@@ -133,7 +133,7 @@ describe('parseEnvString', (): void => {
     const env = parseEnvString('BOB=COOL\nNODE_ENV=dev\nANSWER=42\n')
     assert(env.BOB === 'COOL')
     assert(env.NODE_ENV === 'dev')
-    assert(env.ANSWER === 42)
+    assert(env.ANSWER === '42')
   })
 })
 
@@ -142,29 +142,29 @@ describe('getEnvFileVars', (): void => {
     const env = await getEnvFileVars('./test/test-files/test.json')
     assert.deepEqual(env, {
       THANKS: 'FOR WHAT?!',
-      ANSWER: 42,
+      ANSWER: '42',
       ONLY: 'IN PRODUCTION',
       GALAXY: 'hitch\nhiking',
-      BRINGATOWEL: true,
+      BRINGATOWEL: 'true',
     })
   })
 
   it('should parse a json file keeping all newlines intact', async (): Promise<void> => {
     const env = await getEnvFileVars('./test/test-files/test-newlines.json')
     assert.deepEqual(env, {
       THANKS: 'FOR WHAT?!',
-      ANSWER: 42,
+      ANSWER: '42',
       ONLY: 'IN\n PRODUCTION',
       GALAXY: 'hitch\nhiking\n\n',
-      BRINGATOWEL: true,
+      BRINGATOWEL: 'true',
     })
   })
 
   it('should parse a js/cjs file', async (): Promise<void> => {
     const env = await getEnvFileVars('./test/test-files/test.cjs')
     assert.deepEqual(env, {
       THANKS: 'FOR ALL THE FISH',
-      ANSWER: 0,
+      ANSWER: '0',
       GALAXY: 'hitch\nhiking',
     })
   })
@@ -173,15 +173,15 @@ describe('getEnvFileVars', (): void => {
     const env = await getEnvFileVars('./test/test-files/test-async.cjs')
     assert.deepEqual(env, {
       THANKS: 'FOR ALL THE FISH',
-      ANSWER: 0,
+      ANSWER: '0',
     })
   })
 
   it('should parse a mjs file', async (): Promise<void> => {
     const env = await getEnvFileVars('./test/test-files/test.mjs')
     assert.deepEqual(env, {
       THANKS: 'FOR ALL THE FISH',
-      ANSWER: 0,
+      ANSWER: '0',
       GALAXY: 'hitch\nhiking',
     })
   })
@@ -190,21 +190,21 @@ describe('getEnvFileVars', (): void => {
     const env = await getEnvFileVars('./test/test-files/test-async.mjs')
     assert.deepEqual(env, {
       THANKS: 'FOR ALL THE FISH',
-      ANSWER: 0,
+      ANSWER: '0',
     })
   })
 
   it('should parse an env file', async (): Promise<void> => {
     const env = await getEnvFileVars('./test/test-files/test')
     assert.deepEqual(env, {
       THANKS: 'FOR WHAT?!',
-      ANSWER: 42,
+      ANSWER: '42',
       ONLY: 'IN=PRODUCTION',
       GALAXY: 'hitch\nhiking',
-      BRINGATOWEL: true,
-      a: 1,
-      b: 2,
-      c: 3,
+      BRINGATOWEL: 'true',
+      a: '1',
+      b: '2',
+      c: '3',
       d: "=",
       e: "equals symbol = = ",
       json_no_quotes: "{\"foo\": \"bar\"}",
@@ -223,4 +223,16 @@ describe('getEnvFileVars', (): void => {
       assert.match(e.message, /file path/gi)
     }
   })
+
+  for (const fileExt of ['cjs', 'mjs', 'json']) {
+    it(`should throw an error when importing a ${fileExt} file with an invalid export`, async () => {
+      try {
+        await getEnvFileVars(`./test/test-files/invalid.${fileExt}`)
+        assert.fail('Should not get here!')
+      } catch (e) {
+        assert.instanceOf(e, Error)
+        assert.match(e.message, /does not export an object/gi)
+      }
+    })
+  }
 })

test/test-files/invalid.cjs

@@ -0,0 +1 @@
+module.exports = undefined;

test/test-files/invalid.json

@@ -0,0 +1 @@
+123

test/test-files/invalid.mjs

@@ -0,0 +1 @@
+export default "this is invalid; it's not an object";