Improve performance of toJS (#1453)

lukaswelinder · lukaswelinder · commit 727bb23355bf · 2018-08-24T19:38:01.000-07:00
diff --git a/src/toJS.js b/src/toJS.js
@@ -6,12 +6,17 @@
  */
 
 import { Seq } from './Seq';
+import { isIndexed } from './Predicates';
 import isDataStructure from './utils/isDataStructure';
 
 export function toJS(value) {
-  return isDataStructure(value)
-    ? Seq(value)
-        .map(toJS)
-        .toJSON()
-    : value;
+  if (isDataStructure(value)) {
+    value = Seq(value);
+    const result = isIndexed(value) ? [] : {};
+    value.forEach((v, k) => {
+      result[k] = toJS(v);
+    });
+    return result;
+  }
+  return value;
 }
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))
+  );
 }
