Speedup Dict.mapValues by 15%

Author: DZakh

lib/es6/Stdlib_Dict.js

@@ -15,7 +15,8 @@ function forEachWithKey(dict, f) {
 
 function mapValues(dict, f) {
   let target = {};
-  forEachWithKey(dict, (value, key) => {
+  Object.keys(dict).forEach(key => {
+    let value = dict[key];
     target[key] = f(value);
   });
   return target;

lib/js/Stdlib_Dict.js

@@ -15,7 +15,8 @@ function forEachWithKey(dict, f) {
 
 function mapValues(dict, f) {
   let target = {};
-  forEachWithKey(dict, (value, key) => {
+  Object.keys(dict).forEach(key => {
+    let value = dict[key];
     target[key] = f(value);
   });
   return target;

runtime/Stdlib_Dict.res

@@ -28,6 +28,7 @@ let forEach = (dict, f) => {
   dict->valuesToArray->Stdlib_Array.forEach(value => f(value))
 }
 
+@inline
 let forEachWithKey = (dict, f) => {
   dict->keysToArray->Stdlib_Array.forEach(key => f(dict->getUnsafe(key), key))
 }