fix(state): fixes state merging

package.json

@@ -72,6 +72,7 @@
     "@types/jest": "24.0.11",
     "@types/js-yaml": "3.12.1",
     "@types/lodash.clone": "^4.5.6",
+    "@types/lodash.mergewith": "^4.6.6",
     "@types/object-hash": "^1.2.0",
     "@types/pify": "3.0.2",
     "@typescript-eslint/eslint-plugin": "1.6.0",
@@ -120,6 +121,7 @@
     "find-up": "^3.0.0",
     "fs-extra": "^7.0.1",
     "lodash.clone": "^4.5.0",
+    "lodash.mergewith": "^4.6.1",
     "loglevel": "^1.6.1",
     "object-hash": "^1.3.1",
     "slimconf": "^0.9.0",

src/state/index.ts

@@ -1,5 +1,6 @@
 import load, { ILoad } from './load';
 import { get } from 'slimconf';
+import mergewith from 'lodash.mergewith';
 import { IOptions, IOfType } from '~/types';
 import { DEFAULT_LOG_LEVEL } from '~/constants';
 import hash from 'object-hash';
@@ -12,15 +13,19 @@ export const states = {
     silent: false,
     log: DEFAULT_LOG_LEVEL
   } as IOptions,
-  scope: {} as Partial<IOptions>
+  scope: {} as IOptions
 };
 
+let state: IOptions = {};
+merge();
+
 const cache: IOfType<ILoad> = {};
-let state: IOptions = Object.assign({}, states.base);
 
 export default {
   base(options: IOptions): void {
-    Object.assign(states.base, options);
+    mergewith(states.base, options, (obj, src) => {
+      if (obj === 'undefined') return src;
+    });
     merge();
   },
   scope(options: IOptions): void {
@@ -40,6 +45,7 @@ export default {
 };
 
 function merge(): void {
-  const env = Object.assign({}, states.base.env, states.scope.env);
-  state = Object.assign({}, states.base, states.scope, { env });
+  state = Object.assign({}, states.base, states.scope, {
+    env: Object.assign({}, states.base.env, states.scope.env)
+  });
 }