have prod, test, and dev environment config files override default

config/environment.test.js

 module.exports = {
-  // Angular Universal server settings.
-  ui: {
-    ssl: false,
-    host: 'localhost',
-    port: 3000,
-    // NOTE: Space is capitalized because 'namespace' is a reserved string in TypeScript
-    nameSpace: '/'
-  },
-  // The REST API server settings.
-  rest: {
-    ssl: false,
-    host: 'dspace7.4science.it',
-    port: 80,
-    // NOTE: Space is capitalized because 'namespace' is a reserved string in TypeScript
-    nameSpace: '/dspace-spring-rest/api'
-  },
-  cache: {
-    // NOTE: how long should objects be cached for by default
-    msToLive: 15 * 60 * 1000, // 15 minute
-    control: 'max-age=60' // revalidate browser
-  },
-  logDirectory: '.',
-  // NOTE: rehydrate or replay
-  // rehydrate will transfer prerender state to browser state, actions do not need to replay
-  // replay will transfer an array of actions to browser, actions replay automatically
-  prerenderStrategy: 'rehydrate',
-  // NOTE: will log all redux actions and transfers in console
-  debug: true
+
 };

src/config.ts

@@ -41,7 +41,7 @@ try {
 // if envConfigFile set try to get configs
 if (envConfigFile) {
   try {
-    ENV_CONFIG = configContext(envConfigFile) as GlobalConfig;
+    ENV_CONFIG = Object.assign(ENV_CONFIG, configContext(envConfigFile)) as GlobalConfig;
   } catch (e) {
     console.warn('Cannot find file ' + envConfigFile.substring(2, envConfigFile.length), 'Using default environment.');
   }

yarn.lock

@@ -196,11 +196,7 @@
   version "2.0.29"
   resolved "https://registry.yarnpkg.com/@types/minimatch/-/minimatch-2.0.29.tgz#5002e14f75e2d71e564281df0431c8c1b4a2a36a"
 
-"@types/node@*":
-  version "8.0.13"
-  resolved "https://registry.yarnpkg.com/@types/node/-/node-8.0.13.tgz#530f0f9254209b0335bf5cc6387822594ef47093"
-
-"@types/node@8.0.14":
+"@types/node@*", "@types/node@8.0.14":
   version "8.0.14"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-8.0.14.tgz#4a19dc6bb61d16c01cbadc7b30ac23518fff176b"
 
@@ -7458,7 +7454,7 @@ webpack-merge@4.1.0:
   dependencies:
     lodash "^4.17.4"
 
-webpack-node-externals@^1.6.0:
+webpack-node-externals@1.6.0:
   version "1.6.0"
   resolved "https://registry.yarnpkg.com/webpack-node-externals/-/webpack-node-externals-1.6.0.tgz#232c62ec6092b100635a3d29d83c1747128df9bd"