use toStringTag when available

planttheidea · Sep 30, 2022 · 53be968 · 53be968
1 parent 656aab5
commit 53be968
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Showing 2 changed files with 44 additions and 29 deletions.
diff --git a/src/index.ts b/src/index.ts
@@ -11,15 +11,14 @@ import {
   copySelf,
   copySet,
 } from './copier';
-import { createCache } from './utils';
+import { createCache, getTag } from './utils';
 
 import type { InternalCopier, State } from './copier';
 
 export type { State } from './copier';
 
 const { isArray } = Array;
 const { getPrototypeOf } = Object;
-const { toString } = Object.prototype;
 
 export interface CreateCopierOptions {
   array?: InternalCopier<any[]>;
@@ -51,29 +50,29 @@ export function createCopier(options: CreateCopierOptions) {
     set = copySet,
   } = options;
 
-  const typeSpecificCopiers: Record<string, InternalCopier> = {
-    '[object ArrayBuffer]': arrayBuffer,
-    '[object Blob]': blob,
-    '[object DataView]': dataView,
-    '[object Date]': date,
-    '[object Error]': error,
-    '[object Float32Array]': arrayBuffer,
-    '[object Float64Array]': arrayBuffer,
-    '[object Int8Array]': arrayBuffer,
-    '[object Int16Array]': arrayBuffer,
-    '[object Int32Array]': arrayBuffer,
-    '[object Map]': map,
-    '[object Object]': object,
-    '[object Promise]': copySelf,
-    '[object RegExp]': regExp,
-    '[object Set]': set,
-    '[object WeakMap]': copySelf,
-    '[object WeakSet]': copySelf,
-    '[object Uint8Array]': arrayBuffer,
-    '[object Uint8ClampedArray]': arrayBuffer,
-    '[object Uint16Array]': arrayBuffer,
-    '[object Uint32Array]': arrayBuffer,
-    '[object Uint64Array]': arrayBuffer,
+  const tagSpecificCopiers: Record<string, InternalCopier> = {
+    ArrayBuffer: arrayBuffer,
+    Blob: blob,
+    DataView: dataView,
+    Date: date,
+    Error: error,
+    Float32Array: arrayBuffer,
+    Float64Array: arrayBuffer,
+    Int8Array: arrayBuffer,
+    Int16Array: arrayBuffer,
+    Int32Array: arrayBuffer,
+    Map: map,
+    Object: object,
+    Promise: copySelf,
+    RegExp: regExp,
+    Set: set,
+    WeakMap: copySelf,
+    WeakSet: copySelf,
+    Uint8Array: arrayBuffer,
+    Uint8ClampedArray: arrayBuffer,
+    Uint16Array: arrayBuffer,
+    Uint32Array: arrayBuffer,
+    Uint64Array: arrayBuffer,
   };
 
   function copier(value: any, state: State): any {
@@ -100,11 +99,10 @@ export function createCopier(options: CreateCopierOptions) {
       return array(value, state);
     }
 
-    const objectType = toString.call(value);
-    const typeSpecificCopier = typeSpecificCopiers[objectType];
+    const tagSpecificCopier = tagSpecificCopiers[getTag(value)];
 
-    if (typeSpecificCopier) {
-      return typeSpecificCopier(value, state);
+    if (tagSpecificCopier) {
+      return tagSpecificCopier(value, state);
     }
 
     return typeof value.then === 'function' ? value : object(value, state);

diff --git a/src/utils.ts b/src/utils.ts
@@ -8,6 +8,7 @@ export interface Cache {
 
 const { toString: toStringFunction } = Function.prototype;
 const { create } = Object;
+const { toString: toStringObject } = Object.prototype;
 
 class LegacyCache {
   _keys: any[] = [];
@@ -99,3 +100,19 @@ function getRegExpFlagsModern(regExp: RegExp): string {
  */
 export const getRegExpFlags =
   /test/g.flags === 'g' ? getRegExpFlagsModern : getRegExpFlagsLegacy;
+
+function getTagLegacy(value: any): string {
+  const type = toStringObject.call(value);
+
+  return type.substring(8, type.length - 1);
+}
+
+function getTagModern(value: any): string {
+  return value[Symbol.toStringTag] || getTagLegacy(value);
+}
+
+/**
+ * Get the tag of the value passed, so that the correct copier can be used.
+ */
+export const getTag =
+  typeof Symbol !== 'undefined' ? getTagModern : getTagLegacy;