feat: add isPlainObject

src/index.ts

@@ -17,6 +17,7 @@ export { default as isNil } from './isNil'
 export { default as isNull } from './isNull'
 export { default as isNumber } from './isNumber'
 export { default as isObject } from './isObject'
+export { default as isPlainObject } from './isPlainObject'
 export { default as isRegExp } from './isRegExp'
 export { default as isString } from './isString'
 export { default as isUndefined } from './isUndefined'

src/isPlainObject.ts

@@ -0,0 +1,17 @@
+/**
+ * 检查 value 是否是一个普通对象。
+ *
+ * @param value 要检查的值
+ * @returns 是（true）或否（false）
+ */
+export default function isPlainObject(value: any): value is object {
+  if (!value || typeof value !== 'object') {
+    return false
+  }
+  const proto = Object.getPrototypeOf(value)
+  if (proto === null) {
+    return true
+  }
+  const Ctor = proto.constructor
+  return typeof Ctor === 'function' && Ctor instanceof Ctor
+}

test/index.test.ts

@@ -293,6 +293,24 @@ describe('isObject', () => {
   })
 })
 
+describe('isPlainObject', () => {
+  test('是', () => {
+    expect(vtils.isPlainObject({})).toBeTruthy()
+    expect(vtils.isPlainObject({ x: 1 })).toBeTruthy()
+    expect(vtils.isPlainObject(Object.create(null))).toBeTruthy()
+    expect(vtils.isPlainObject(Object({ x: 1 }))).toBeTruthy()
+  })
+  test('不是', () => {
+    const MyCls = class Cls {}
+    expect(vtils.isPlainObject('str')).toBeFalsy()
+    expect(vtils.isPlainObject(2)).toBeFalsy()
+    expect(vtils.isPlainObject(null)).toBeFalsy()
+    expect(vtils.isPlainObject(Date)).toBeFalsy()
+    expect(vtils.isPlainObject(() => ({}))).toBeFalsy()
+    expect(vtils.isPlainObject(MyCls)).toBeFalsy()
+  })
+})
+
 describe('isDate', () => {
   test('是', () => {
     expect(vtils.isDate(now)).toBeTruthy()