Merge pull request #4012 from ooflorent/fix/cache-ie11

Work around spec non-compliance of Map#set and Set#add in IE11.

package.json

@@ -29,7 +29,7 @@
     {
       "name": "apollo-cache-inmemory",
       "path": "./packages/apollo-cache-inmemory/lib/bundle.min.js",
-      "maxSize": "6.75 kB"
+      "maxSize": "7 kB"
     },
     {
       "name": "apollo-client",

packages/apollo-cache-inmemory/src/fixPolyfills.ts

@@ -1,6 +1,25 @@
-const frozen = {};
-const frozenTestMap = new Map();
+// Make sure Map.prototype.set returns the Map instance, per spec.
+// https://github.com/apollographql/apollo-client/issues/4024
+const testMap = new Map();
+if (testMap.set(1, 2) !== testMap) {
+  const { set } = testMap;
+  Map.prototype.set = function (...args) {
+    set.apply(this, args);
+    return this;
+  };
+}
 
+// Make sure Set.prototype.add returns the Set instance, per spec.
+const testSet = new Set();
+if (testSet.add(3) !== testSet) {
+  const { add } = testSet;
+  Set.prototype.add = function (...args) {
+    add.apply(this, args);
+    return this;
+  };
+}
+
+const frozen = {};
 if (typeof Object.freeze === 'function') {
   Object.freeze(frozen);
 }
@@ -12,13 +31,13 @@ try {
   // objects before they become non-extensible:
   // https://github.com/facebook/react-native/blob/98a6f19d7c/Libraries/vendor/core/Map.js#L44-L50
   // https://github.com/apollographql/react-apollo/issues/2442#issuecomment-426489517
-  frozenTestMap.set(frozen, frozen).delete(frozen);
+  testMap.set(frozen, frozen).delete(frozen);
 } catch {
   const wrap = (method: <T>(obj: T) => T): typeof method => {
     return method && (obj => {
       try {
         // If .set succeeds, also call .delete to avoid leaking memory.
-        frozenTestMap.set(obj, obj).delete(obj);
+        testMap.set(obj, obj).delete(obj);
       } finally {
         // If .set or .delete fails, the exception will be silently swallowed
         // by this return-from-finally statement:

packages/apollo-cache-inmemory/src/optimism.ts

@@ -1,7 +1,7 @@
 declare function require(id: string): any;
 
 export type OptimisticWrapperFunction<
-  T = (...args: any[]) => any,
+  T = (...args: any[]) => any
 > = T & {
   // The .dirty(...) method of an optimistic function takes exactly the same
   // parameter types as the original function.
@@ -14,7 +14,9 @@ export type OptimisticWrapOptions = {
   makeCacheKey?(...args: any[]): any;
 };
 
-const { wrap }: {
+const {
+  wrap,
+}: {
   wrap<T>(
     originalFunction: T,
     options?: OptimisticWrapOptions,
@@ -40,7 +42,11 @@ export class CacheKeyNode<KeyType = object> {
   }
 
   getOrCreate(value: any): CacheKeyNode<KeyType> {
-    const map = this.children || (this.children = new Map);
-    return map.get(value) || map.set(value, new CacheKeyNode<KeyType>()).get(value);
+    const map = this.children || (this.children = new Map());
+    let node = map.get(value);
+    if (!node) {
+      map.set(value, node = new CacheKeyNode<KeyType>());
+    }
+    return node;
   }
 }