refactor: option merging + extract helper functions

packages/observer/src/baseHandlers.ts

@@ -2,6 +2,7 @@ import { observable, immutable, unwrap } from './index'
 import { OperationTypes } from './operations'
 import { track, trigger } from './autorun'
 import { LOCKED } from './lock'
+import { isObject } from '@vue/shared'
 
 const hasOwnProperty = Object.prototype.hasOwnProperty
 
@@ -18,7 +19,7 @@ function createGetter(isImmutable: boolean) {
       return res
     }
     track(target, OperationTypes.GET, key)
-    return res !== null && typeof res === 'object'
+    return isObject(res)
       ? isImmutable
         ? // need to lazy access immutable and observable here to avoid
           // circular dependency

packages/observer/src/collectionHandlers.ts

@@ -2,8 +2,8 @@ import { unwrap, observable, immutable } from './index'
 import { track, trigger } from './autorun'
 import { OperationTypes } from './operations'
 import { LOCKED } from './lock'
+import { isObject } from '@vue/shared'
 
-const isObject = (value: any) => value !== null && typeof value === 'object'
 const toObservable = (value: any) =>
   isObject(value) ? observable(value) : value
 const toImmutable = (value: any) => (isObject(value) ? immutable(value) : value)

packages/observer/src/index.ts

@@ -1,3 +1,4 @@
+import { isObject, EMPTY_OBJ } from '@vue/shared'
 import { mutableHandlers, immutableHandlers } from './baseHandlers'
 
 import {
@@ -28,7 +29,6 @@ export { OperationTypes } from './operations'
 export { computed, ComputedGetter } from './computed'
 export { lock, unlock } from './lock'
 
-const EMPTY_OBJ = {}
 const collectionTypes: Set<any> = new Set([Set, Map, WeakMap, WeakSet])
 const observableValueRE = /^\[object (?:Object|Array|Map|Set|WeakMap|WeakSet)\]$/
 
@@ -83,7 +83,7 @@ function createObservable(
   baseHandlers: ProxyHandler<any>,
   collectionHandlers: ProxyHandler<any>
 ) {
-  if (target === null || typeof target !== 'object') {
+  if (!isObject(target)) {
     if (__DEV__) {
       console.warn(`value is not observable: ${String(target)}`)
     }