fix(breaking): convert .env variables to uppercase before hoisting (#61)

Co-authored-by: Michael Goberling <mgoberling@Michaels-MacBook-Pro-3.local>
Co-authored-by: Shazron Abdullah <36107+shazron@users.noreply.github.com>

Author: 3 people

README.md

@@ -68,7 +68,24 @@ Local configuration is loaded from **$PWD/.aio**
 
 ### Dot Env Configuration
 
-A local .env file is also loaded.  This file can contain environmental variables
+A local .env file is also loaded.  This file can contain environmental variables.
+
+Note: All environment variable names will be converted to uppercase. 
+
+1. In the event that there are duplicate environment variables, if the uppercase version exists, it will be hoisted. 
+
+```
+aa=1 
+aA=2
+AA=3 <-- Hoisted as AA
+```
+
+2. In the event that there are duplicate environment variables with multiple case variations, the first entry will be hoisted. 
+
+```
+aa=1 <-- Hoisted as AA
+Aa=2
+```
 
 ## Resolving Values
 

src/dotenv.js

@@ -94,6 +94,18 @@ module.exports = function(force = false) {
     try {
       clear()
       const envs = parse(file)
+
+      // Convert envs to uppercase
+      for (const key in envs) {
+        const keyName = key
+        const uppercaseKeyName = keyName.toUpperCase()
+        const keyValue = envs[key]
+        if (!(uppercaseKeyName in envs)) {
+          envs[uppercaseKeyName] = keyValue
+          delete envs[keyName]
+        }
+      }
+
       const newKeys = diff(envs, process.env).sort()
 
       debug(`loading environment variables from ${file}`)

test/__fixtures__/lowercase

@@ -0,0 +1,4 @@
+a_a=
+b_b=
+c_c=
+d_d=

test/__fixtures__/lowercase_dup_already_exists

@@ -0,0 +1,3 @@
+A_A=1
+a_a=2
+A_a=3

test/__fixtures__/lowercase_dup_last_variation

@@ -0,0 +1,2 @@
+a_a=1
+A_a=2

test/dotenv.js

@@ -120,6 +120,27 @@ describe('parse', () => {
     expect(process.env.D).toEqual('')
   })
 
+  test('converts lowercase names to uppercase names', () => {
+    fs.writeFileSync('/project/.env', fixtureFile('lowercase'))
+    dotenv()
+    expect(process.env.A_A).toEqual('')
+    expect(process.env.B_B).toEqual('')
+    expect(process.env.C_C).toEqual('')
+    expect(process.env.D_D).toEqual('')
+  })
+
+  test('hoists existing uppercase, ignores other case variations', () => {
+    fs.writeFileSync('/project/.env', fixtureFile('lowercase_dup_already_exists'))
+    dotenv()
+    expect(process.env.A_A).toEqual('1')
+  })
+
+  test('hoists first of variations, ignores other case variations', () => {
+    fs.writeFileSync('/project/.env', fixtureFile('lowercase_dup_last_variation'))
+    dotenv()
+    expect(process.env.A_A).toEqual('1')
+  })
+
   test('comment', () => {
     fs.writeFileSync('/project/.env', fixtureFile('comment'))
     dotenv()