feat: add env prefix option (#428)

* feat: add env prefix option

* chore: remove console.log from test

Author: dderevjanik

lib/nconf/stores/env.js

@@ -20,7 +20,7 @@ var Env = exports.Env = function (options) {
 
   options        = options || {};
   this.type      = 'env';
-  this.readOnly  = true;
+  this.readOnly  = options.readOnly !== undefined ? options.readOnly : true;
   this.whitelist = options.whitelist || [];
   this.separator = options.separator || '';
   this.lowerCase = options.lowerCase || false;
@@ -61,6 +61,15 @@ Env.prototype.loadEnv = function () {
 
   var env = process.env;
 
+  if (this.prefix) {
+    env = {};
+    Object.keys(process.env).forEach(function (key) {
+      if (key.indexOf(self.prefix) === 0) {
+        env[key.replace(self.prefix, '')] = process.env[key];
+      } 
+    });
+  }
+
   if (this.lowerCase) {
     env = {};
     Object.keys(process.env).forEach(function (key) {
@@ -102,4 +111,3 @@ Env.prototype.loadEnv = function () {
   this.readOnly = true;
   return this.store;
 };
-

test/stores/env.test.js

@@ -0,0 +1,50 @@
+/*
+ * env-test.js: Tests for the nconf env store.
+ *
+ * (C) 2011, Charlie Robbins and the Contributors.
+ *
+ */
+
+var nconf = require('../../lib/nconf');
+
+process.env.DEEP__NESTED__VALUE = 'foo';
+process.env.DEEP2__NESTED__VALUE = 'bar';
+
+describe('nconf/stores/env, An instance of nconf.Env', () => {
+  it("should have the correct methods defined", () => {
+    var env = new nconf.Env();
+    expect(typeof env.loadSync).toBe('function');
+    expect(typeof env.loadEnv).toBe('function');
+    expect(env.whitelist instanceof Array).toBeTruthy();
+    expect(env.whitelist.length).toEqual(0);
+    expect(env.inputSeparator).toEqual('__');
+  });
+  it("should have the correct methods defined and with readOnly false", () => {
+    var env = new nconf.Env({readOnly: false});
+    expect(typeof env.loadSync).toBe('function');
+    expect(typeof env.loadEnv).toBe('function');
+    expect(env.whitelist instanceof Array).toBeTruthy();
+    expect(env.whitelist.length).toEqual(0);
+    expect(env.inputSeparator).toEqual('__');
+    expect(env.readOnly).toBe(false);
+  });
+  it("should be able to retrieve a value using the logical separator", () => {
+    var env = new nconf.Env({accessSeparator: '.', inputSeparator: '__'});
+    env.loadSync();
+
+    expect(env.accessSeparator).toBe('.');
+    expect(env.get('DEEP.NESTED.VALUE')).toBe('foo');
+  });
+  it("should filter and strip prefix from environment variables", () => {
+    var env = new nconf.Env({prefix: 'DEEP2__'});
+    env.loadSync();
+    expect(env.get('DEEP__NESTED__VALUE')).toBeUndefined();
+    expect(env.get('NESTED__VALUE')).toBe('bar');
+  });
+  it("should filter and strip prefix from environment variables with input and access separator", () => {
+    var env = new nconf.Env({prefix: 'DEEP2__', accessSeparator: '.', inputSeparator: '__' });
+    env.loadSync();
+    expect(env.get('DEEP.NESTED.VALUE')).toBeUndefined();
+    expect(env.get('NESTED.VALUE')).toBe('bar');
+  });
+});