feat: new isPrimitive and objectId function

Author: antfu

src/is.test.ts

@@ -0,0 +1,18 @@
+import { expect, it } from 'vitest'
+import { isPrimitive } from './is'
+
+it('isPrimitive', () => {
+  expect(isPrimitive(null)).toBe(true)
+  expect(isPrimitive(undefined)).toBe(true)
+  expect(isPrimitive(0)).toBe(true)
+  expect(isPrimitive('')).toBe(true)
+  expect(isPrimitive(Symbol('foo'))).toBe(true)
+  expect(isPrimitive(1n)).toBe(true)
+
+  expect(isPrimitive([])).toBe(false)
+  expect(isPrimitive({})).toBe(false)
+
+  class Foo {}
+  expect(isPrimitive(new Foo())).toBe(false)
+  expect(isPrimitive(new Map())).toBe(false)
+})

src/is.ts

@@ -12,6 +12,13 @@ export const isNull = (val: any): val is null => toString(val) === '[object Null
 export const isRegExp = (val: any): val is RegExp => toString(val) === '[object RegExp]'
 export const isDate = (val: any): val is Date => toString(val) === '[object Date]'
 
+/**
+ * Check if a value is primitive
+ */
+export function isPrimitive(val: any): val is string | number | boolean | symbol | bigint | null | undefined {
+  return !val || Object(val) !== val
+}
+
 // @ts-expect-error
 export const isWindow = (val: any): boolean => typeof window !== 'undefined' && toString(val) === '[object Window]'
 // @ts-expect-error

src/object.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest'
-import { deepMerge, deepMergeWithArray, objectMap } from './object'
+import { deepMerge, deepMergeWithArray, objectId, objectMap } from './object'
 
 it('objectMap', () => {
   expect(objectMap({}, (...args) => args)).toEqual({})
@@ -77,3 +77,19 @@ describe('deepMergeWithArray', () => {
     expect(deepMergeWithArray({}, obj1, obj2)).toEqual({ a: ['A', 'B', 'C'], b: ['D'] })
   })
 })
+
+it('objectId', () => {
+  const foo = { a: 1, b: 2 }
+  const bar = new Map()
+  // eslint-disable-next-line prefer-regex-literals
+  const baz = new RegExp('foo', 'g')
+
+  expect(objectId(foo)).toBe(objectId(foo))
+  expect(objectId(bar)).toBe(objectId(bar))
+  expect(objectId(baz)).toBe(objectId(baz))
+
+  expect(objectId(foo)).not.toBe(objectId(bar))
+  expect(objectId({})).not.toBe(objectId({}))
+  expect(objectId([])).not.toBe(objectId([]))
+  expect(objectId(/a/)).not.toBe(objectId(/a/))
+})

src/object.ts

@@ -1,6 +1,7 @@
 import type { DeepMerge } from './types'
 import { notNullish } from './guards'
-import { isObject } from './is'
+import { isObject, isPrimitive } from './is'
+import { randomStr } from './string'
 
 /**
  * Map key/value pairs for an object, and construct a new one
@@ -211,3 +212,22 @@ export function hasOwnProperty<T>(obj: T, v: PropertyKey) {
     return false
   return Object.prototype.hasOwnProperty.call(obj, v)
 }
+
+const _objectIdMap = /* @__PURE__ */ new WeakMap<WeakKey, string>()
+/**
+ * Get an object's unique identifier
+ *
+ * Same object will always return the same id
+ *
+ * Expect argument to be a non-primitive object/array. Primitive values will be returned as is.
+ *
+ * @category Object
+ */
+export function objectId(obj: WeakKey): string {
+  if (isPrimitive(obj))
+    return obj as unknown as string
+  if (!_objectIdMap.has(obj)) {
+    _objectIdMap.set(obj, randomStr())
+  }
+  return _objectIdMap.get(obj)!
+}

tsconfig.json

@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "target": "es2018",
+    "target": "es2020",
     "lib": ["esnext"],
     "module": "esnext",
     "moduleResolution": "node",