Make ObservableSet backport compatible with IE11

src/api/object-api.ts

@@ -12,6 +12,7 @@ import {
     endBatch,
     defineObservableProperty,
     invariant,
+    iteratorToArray,
     getAdministration,
     ObservableObjectAdministration
 } from "../internal"
@@ -28,7 +29,7 @@ export function keys(obj: any): any {
         return (obj as any)._keys.slice()
     }
     if (isObservableSet(obj)) {
-        return Array.from(obj.keys())
+        return iteratorToArray(obj.keys())
     }
     if (isObservableArray(obj)) {
         return obj.map((_, index) => index)
@@ -51,7 +52,7 @@ export function values(obj: any): string[] {
         return keys(obj).map(key => obj.get(key))
     }
     if (isObservableSet(obj)) {
-        return Array.from(obj.values())
+        return iteratorToArray(obj.values())
     }
     if (isObservableArray(obj)) {
         return obj.slice()
@@ -74,7 +75,7 @@ export function entries(obj: any): any {
         return keys(obj).map(key => [key, obj.get(key)])
     }
     if (isObservableSet(obj)) {
-        return Array.from(obj.entries())
+        return iteratorToArray(obj.entries())
     }
     if (isObservableArray(obj)) {
         return obj.map((key, index) => [index, key])

src/types/observableset.ts

@@ -26,7 +26,8 @@ import {
     isES6Set,
     toStringTagSymbol,
     declareIterator,
-    addHiddenFinalProp
+    addHiddenFinalProp,
+    iteratorToArray
 } from "../internal"
 
 const ObservableSetMarker = {}
@@ -192,8 +193,8 @@ export class ObservableSet<T = any> implements Set<T>, IInterceptable<ISetWillCh
 
     entries() {
         let nextIndex = 0
-        const keys = Array.from(this.keys())
-        const values = Array.from(this.values())
+        const keys = iteratorToArray(this.keys())
+        const values = iteratorToArray(this.values())
         return makeIterable<[T, T]>({
             next() {
                 const index = nextIndex
@@ -213,7 +214,15 @@ export class ObservableSet<T = any> implements Set<T>, IInterceptable<ISetWillCh
         this._atom.reportObserved()
         const self = this
         let nextIndex = 0
-        const observableValues = Array.from(this._data.values())
+        let observableValues: any[]
+
+        if (this._data.values !== undefined) {
+            observableValues = iteratorToArray(this._data.values())
+        } else {
+            // There is no values function in IE11
+            observableValues = []
+            this._data.forEach(e => observableValues.push(e))
+        }
         return makeIterable<T>({
             next() {
                 return nextIndex < observableValues.length
@@ -262,7 +271,7 @@ export class ObservableSet<T = any> implements Set<T>, IInterceptable<ISetWillCh
     }
 
     toString(): string {
-        return this.name + "[ " + Array.from(this).join(", ") + " ]"
+        return this.name + "[ " + iteratorToArray(this.keys()).join(", ") + " ]"
     }
 }
 

src/utils/eq.ts

@@ -134,7 +134,7 @@ function deepEq(a: any, b: any, aStack?: any[], bStack?: any[]) {
 function unwrap(a: any) {
     if (isObservableArray(a)) return a.peek()
     if (isES6Map(a) || isObservableMap(a)) return iteratorToArray(a.entries())
-    if (isES6Set(a) || isObservableSet(a)) return Array.from(a.entries())
+    if (isES6Set(a) || isObservableSet(a)) return iteratorToArray(a.entries())
     return a
 }
 

src/utils/utils.ts

@@ -173,7 +173,7 @@ export function getMapLikeKeys(map: any): any {
 }
 
 // use Array.from in Mobx 5
-export function iteratorToArray<T>(it: Iterator<T>): ReadonlyArray<T> {
+export function iteratorToArray<T>(it: Iterator<T>): Array<T> {
     const res: T[] = []
     while (true) {
         const r: any = it.next()