Fix slow iterator for Set (immutable-js#1333)

leebyron · web-flow · commit b9dabc177570 · 2017-10-04T14:19:13.000-07:00
Replace's Set's internal representation of Map<V, true> to Map<V, V>, which more closely mirrors Set's own representation of presenting keys and values as the same value. Fixes immutable-js#1249
diff --git a/src/Set.js b/src/Set.js
@@ -64,7 +64,7 @@ export class Set extends SetCollection {
   // @pragma Modification
 
   add(value) {
-    return updateSet(this, this._map.set(value, true));
+    return updateSet(this, this._map.set(value, value));
   }
 
   remove(value) {
@@ -150,11 +150,11 @@ export class Set extends SetCollection {
   }
 
   __iterate(fn, reverse) {
-    return this._map.__iterate((_, k) => fn(k, k, this), reverse);
+    return this._map.__iterate(k => fn(k, k, this), reverse);
   }
 
   __iterator(type, reverse) {
-    return this._map.map((_, k) => k).__iterator(type, reverse);
+    return this._map.__iterator(type, reverse);
   }
 
   __ensureOwner(ownerID) {

Original file line number	Diff line number	Diff line change
`@@ -64,7 +64,7 @@ export class Set extends SetCollection {`
`64`	`64`	`// @pragma Modification`
`65`	`65`
`66`	`66`	`add(value) {`
`67`		`- return updateSet(this, this._map.set(value, true));`
	`67`	`+ return updateSet(this, this._map.set(value, value));`
`68`	`68`	`}`
`69`	`69`
`70`	`70`	`remove(value) {`
`@@ -150,11 +150,11 @@ export class Set extends SetCollection {`
`150`	`150`	`}`
`151`	`151`
`152`	`152`	`__iterate(fn, reverse) {`
`153`		`- return this._map.__iterate((_, k) => fn(k, k, this), reverse);`
	`153`	`+ return this._map.__iterate(k => fn(k, k, this), reverse);`
`154`	`154`	`}`
`155`	`155`
`156`	`156`	`__iterator(type, reverse) {`
`157`		`- return this._map.map((_, k) => k).__iterator(type, reverse);`
	`157`	`+ return this._map.__iterator(type, reverse);`
`158`	`158`	`}`
`159`	`159`
`160`	`1 39F0 60`	`__ensureOwner(ownerID) {`