ticket #36 : ajout d'un iterateur de tableau commençant par la fin

spec/iterator.spec.ts

+/// <reference path="../node_modules/@types/jasmine/index.d.ts" />
+
+import { ArrayReverseIterator } from "../src/util/iterator";
+
+describe('iterator : ', () => {
+    it("reverse ( undefined )", () => {
+        const arr: Object[] = undefined;
+        const it = new ArrayReverseIterator<Object>(arr);
+        expect(it.next().done).toBeTruthy();
+    });
+
+    it("reverse( [] )", () => {
+        const arr: Object[] = [];
+        const it = new ArrayReverseIterator<Object>(arr);
+        expect(it.next().done).toBeTruthy();
+    });
+
+    it("reverse( [1] )", () => {
+        const arr: number[] = [1];
+        const it = new ArrayReverseIterator<number>(arr);
+        const v1 = it.next();
+        expect(v1.done).toBeFalsy();
+        expect(v1.value).toEqual(1);
+        const v2 = it.next();
+        expect(v2.done).toBeTruthy();
+    });
+
+    it("reverse( [1,2] )", () => {
+        const arr: number[] = [1, 2];
+        const it = new ArrayReverseIterator<number>(arr);
+        const v1 = it.next();
+        expect(v1.done).toBeFalsy();
+        expect(v1.value).toEqual(2);
+        const v2 = it.next();
+        expect(v2.done).toBeFalsy();
+        expect(v2.value).toEqual(1);
+        const v3 = it.next();
+        expect(v3.done).toBeTruthy();
+    });
+});

src/index.ts

@@ -22,3 +22,4 @@ export * from "./util/pair";
 export * from "./util/interval";
 export * from "./pab/pab_dimension";
 export * from "./pab/pab_puissance";
+export * from "./util/iterator";

src/util/iterator.ts

+export class ArrayReverseIterator<T> implements IterableIterator<T> {
+    private _index: number;
+
+    constructor(private _arr: any[]) {
+        this._index = this._arr == undefined ? 0 : this._arr.length - 1;
+    }
+
+    public next(): IteratorResult<T> {
+        if (this._arr != undefined && this._index >= 0) {
+            return {
+                done: false,
+                value: this._arr[this._index--]
+            }
+        } else {
+            return {
+                done: true,
+                value: null
+            }
+        }
+    }
+
+    [Symbol.iterator](): IterableIterator<T> {
+        return this;
+    }
+}

tsconfig.json

 {
   "compilerOptions": {
-    "target": "es5",
+    "target": "es6",
     "module": "commonjs",
     "outDir": "./build",
     "noImplicitAny": true,
@@ -12,4 +12,4 @@
   "exclude": [
     "node_modules"
   ]
-}
+}
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