Improve performance of toJS (#1581)

leebyron · leebyron · commit 43835aa4da6d · 2018-09-18T13:10:43.000-07:00
Fixes #1453 commit b600bd7c56da9f71d19a035838523610d4c96c00 Author: Lee Byron <lee.byron@robinhood.com> Date: Tue Sep 18 12:54:40 2018 -0700 Further improvements commit 9c6395b4baba8a79b3b364d68a4909a26ce7b51c Merge: ca85e75 26ecbab Author: Lee Byron <lee.byron@robinhood.com> Date: Tue Sep 18 12:28:49 2018 -0700 Merge branch 'toJS-performance' of https://github.com/lukaswelinder/immutable-js into lukaswelinder-toJS-performance commit 26ecbab Author: Lukas Welinder <lukas@welinder.co> Date: Fri Aug 24 20:28:00 2018 -0700 Resolve issue w/ toJS handling structures that should become arrays commit 1c56169 Author: Lukas Welinder <lukas@welinder.co> Date: Fri Aug 24 20:11:42 2018 -0700 Resolve issue w/ toJS handling structures that should become arrays commit 0b44fad Author: Lukas Welinder <lukas@welinder.co> Date: Fri Aug 24 20:01:39 2018 -0700 Revert "Adjust type check approach for toJS performance fix" This reverts commit 0ca7f5d commit 0ca7f5d Author: Lukas Welinder <lukas@welinder.co> Date: Fri Aug 24 19:57:19 2018 -0700 Adjust type check approach for toJS performance fix commit 727bb23 Author: Lukas Welinder <lukas@welinder.co> Date: Fri Aug 24 19:38:01 2018 -0700 Improve performance of toJS (#1453)
diff --git a/perf/toJS.js b/perf/toJS.js
@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+describe('toJS', () => {
+  const array32 = [];
+  for (let ii = 0; ii < 32; ii++) {
+    array32[ii] = ii;
+  }
+  const list = Immutable.List(array32);
+
+  it('List of 32', () => {
+    Immutable.toJS(list);
+  });
+
+  const obj32 = {};
+  for (let ii = 0; ii < 32; ii++) {
+    obj32[ii] = ii;
+  }
+  const map = Immutable.Map(obj32);
+
+  it('Map of 32', () => {
+    Immutable.toJS(map);
+  });
+});
diff --git a/src/toJS.js b/src/toJS.js
@@ -6,12 +6,29 @@
  */
 
 import { Seq } from './Seq';
+import { isCollection, isKeyed } from './Predicates';
 import isDataStructure from './utils/isDataStructure';
 
 export function toJS(value) {
-  return isDataStructure(value)
-    ? Seq(value)
-        .map(toJS)
-        .toJSON()
-    : value;
+  if (!value || typeof value !== 'object') {
+    return value;
+  }
+  if (!isCollection(value)) {
+    if (!isDataStructure(value)) {
+      return value;
+    }
+    value = Seq(value);
+  }
+  if (isKeyed(value)) {
+    const result = {};
+    value.__iterate((v, k) => {
+      result[k] = toJS(v);
+    });
+    return result;
+  }
+  const result = [];
+  value.__iterate(v => {
+    result.push(toJS(v));
+  });
+  return result;
 }
diff --git a/src/utils/isDataStructure.js b/src/utils/isDataStructure.js
@@ -13,5 +13,8 @@ import isPlainObj from './isPlainObj';
  * provided by Immutable.js or a plain Array or Object.
  */
 export default function isDataStructure(value) {
-  return isImmutable(value) || Array.isArray(value) || isPlainObj(value);
+  return (
+    typeof value === 'object' &&
+    (isImmutable(value) || Array.isArray(value) || isPlainObj(value))
+  );
 }
