[FIX/IMP]: t-foreach can interpret any iterable.

t-foreach accepted only arrays and object.
Now, iterables and objects are accepted.

Closes #720

src/component/directive.ts

@@ -400,7 +400,6 @@ QWeb.addDirective({
 
     if (hasSlots) {
       const clone = <Element>node.cloneNode(true);
-      const slotNodes = Array.from(clone.querySelectorAll("[t-set-slot]"));
 
       // The next code is a fallback for compatibility reason. It accepts t-set
       // elements that are direct children with a non empty body as nodes defining
@@ -410,26 +409,43 @@ QWeb.addDirective({
       // code using slots. This will be removed in v2.0 someday. Meanwhile,
       // please use t-set-slot everywhere you need to set the content of a
       // slot.
-      for (let el of clone.children) {
+      for (let node of clone.children) {
-        if (el.getAttribute("t-set") && el.hasChildNodes()) {
+        if (node.hasAttribute("t-set") && node.hasChildNodes()) {
-          slotNodes.push(el);
+          node.setAttribute("t-set-slot", node.getAttribute("t-set")!);
+          node.removeAttribute("t-set");
         }
       }
+      const slotNodes = Array.from(clone.querySelectorAll("[t-set-slot]"));
+      const slotNames = new Set<string>();
       const slotId = QWeb.nextSlotId++;
       ctx.addLine(`w${componentID}.__owl__.slotId = ${slotId};`);
       if (slotNodes.length) {
         for (let i = 0, length = slotNodes.length; i < length; i++) {
           const slotNode = slotNodes[i];
-          slotNode.parentElement!.removeChild(slotNode);
+          // check if this is defined in a sub component (in which case it should
-          let key = slotNode.getAttribute("t-set-slot")!;
+          // be ignored)
-          slotNode.removeAttribute("t-set-slot");
+          let el = slotNode.parentElement;
-
+          let isInSubComponent = false;
-          // here again, this code should be removed when we stop supporting
+          while (el !== clone) {
-          // using t-set to define the content of named slots.
+            if (
-          if (!key) {
+              el!.hasAttribute("t-component") ||
-            key = slotNode.getAttribute("t-set")!;
+              el!.tagName[0] === el!.tagName[0].toUpperCase()
-            slotNode.removeAttribute("t-set");
+            ) {
+              isInSubComponent = true;
+              break;
+            }
           }
+          if (isInSubComponent) {
+            continue;
+          }
+          let key = slotNode.getAttribute("t-set-slot")!;
+          if (slotNames.has(key)) {
+            continue;
+          }
+          slotNames.add(key);
+          slotNode.removeAttribute("t-set-slot");
+          slotNode.parentElement!.removeChild(slotNode);
+
           const slotFn = qweb._compile(`slot_${key}_template`, slotNode, ctx);
           QWeb.slots[`${slotId}_${key}`] = slotFn;
         }

src/qweb/base_directives.ts

@@ -312,9 +312,13 @@ QWeb.addDirective({
     let valuesID = ctx.generateID();
     ctx.addLine(`let _${keysID} = _${valuesID} = _${arrayID};`);
     ctx.addIf(`!(_${arrayID} instanceof Array)`);
+    ctx.addIf(`typeof _${arrayID}[Symbol.iterator] === 'function'`);
+    ctx.addLine(`_${keysID} = [..._${arrayID}];`)
+    ctx.addElse();
     ctx.addLine(`_${keysID} = Object.keys(_${arrayID});`);
     ctx.addLine(`_${valuesID} = Object.values(_${arrayID});`);
     ctx.closeIf();
+    ctx.closeIf();
     ctx.addLine(`let _length${keysID} = _${keysID}.length;`);
     let varsID = ctx.startProtectScope(true);
     const loopVar = `i${ctx.loopNumber}`;

tests/component/__snapshots__/component.test.ts.snap

@@ -53,8 +53,12 @@ exports[`basic widget properties reconciliation alg works for t-foreach in t-for
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -70,8 +74,12 @@ exports[`basic widget properties reconciliation alg works for t-foreach in t-for
         if (!_6) { throw new Error('QWeb error: Invalid loop expression')}
         let _7 = _8 = _6;
         if (!(_6 instanceof Array)) {
-            _7 = Object.keys(_6);
+            if (typeof _6[Symbol.iterator] === 'function') {
-            _8 = Object.values(_6);
+                _7 = [..._6];
+            } else {
+                _7 = Object.keys(_6);
+                _8 = Object.values(_6);
+            }
         }
         let _length7 = _7.length;
         let _origScope9 = scope;
@@ -272,8 +280,12 @@ exports[`composition sub components with some state rendered in a loop 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -558,8 +570,12 @@ exports[`other directives with t-component t-on expression captured in t-foreach
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -600,8 +616,12 @@ exports[`other directives with t-component t-on expression in t-foreach 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -652,8 +672,12 @@ exports[`other directives with t-component t-on expression in t-foreach with t-s
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -705,8 +729,12 @@ exports[`other directives with t-component t-on method call in t-foreach 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -1371,8 +1399,12 @@ exports[`other directives with t-component t-set outside modified in t-foreach 1
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -1521,8 +1553,12 @@ exports[`random stuff/miscellaneous t-on with handler bound to dynamic argument
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -1797,8 +1833,12 @@ exports[`t-model directive in a t-foreach 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -1837,8 +1877,12 @@ exports[`t-model directive in a t-foreach, part 2 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;

tests/component/__snapshots__/slots.test.ts.snap

@@ -348,8 +348,12 @@ exports[`t-slot directive slots are rendered with proper context, part 2 2`] = `
     if (!_3) { throw new Error('QWeb error: Invalid loop expression')}
     let _4 = _5 = _3;
     if (!(_3 instanceof Array)) {
-        _4 = Object.keys(_3);
+        if (typeof _3[Symbol.iterator] === 'function') {
-        _5 = Object.values(_3);
+            _4 = [..._3];
+        } else {
+            _4 = Object.keys(_3);
+            _5 = Object.values(_3);
+        }
     }
     let _length4 = _4.length;
     let _origScope6 = scope;
@@ -445,8 +449,12 @@ exports[`t-slot directive slots are rendered with proper context, part 3 2`] = `
     if (!_3) { throw new Error('QWeb error: Invalid loop expression')}
     let _4 = _5 = _3;
     if (!(_3 instanceof Array)) {
-        _4 = Object.keys(_3);
+        if (typeof _3[Symbol.iterator] === 'function') {
-        _5 = Object.values(_3);
+            _4 = [..._3];
+        } else {
+            _4 = Object.keys(_3);
+            _5 = Object.values(_3);
+        }
     }
     let _length4 = _4.length;
     let _origScope6 = scope;

tests/component/slots.test.ts

@@ -987,4 +987,69 @@ describe("t-slot directive", () => {
 
     expect(fixture.innerHTML).toBe("<div><span><p>sokka</p></span></div>");
   });
+
+  test("named slot inside slot", async () => {
+    class Child extends Component {
+      static template = xml`
+        <div>
+          <t t-slot="brol"/>
+          <t t-slot="default"/>
+        </div>`;
+    }
+    class Parent extends Component {
+      static template = xml`
+        <div>
+          <Child>
+            <t t-set-slot="brol">
+              <p>A<t t-esc="value"/></p>
+            </t>
+            <Child>
+              <t t-set-slot="brol">
+                <p>B<t t-esc="value"/></p>
+              </t>
+            </Child>
+          </Child>
+        </div>`;
+      static components = { Child };
+      value = "blip";
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe("<div><div><p>Ablip</p><div><p>Bblip</p></div></div></div>");
+  });
+
+  test("named slots inside slot, again", async () => {
+    class Child extends Component {
+      static template = xml`
+        <child>
+          <t t-slot="brol1">default1</t>
+          <t t-slot="brol2">default2</t>
+          <t t-slot="default"/>
+        </child>`;
+    }
+    class Parent extends Component {
+      static template = xml`
+        <div>
+          <Child>
+            <t t-set-slot="brol1">
+              <p>A<t t-esc="value"/></p>
+            </t>
+            <Child>
+              <t t-set-slot="brol2">
+                <p>B<t t-esc="value"/></p>
+              </t>
+            </Child>
+          </Child>
+        </div>`;
+      static components = { Child };
+      value = "blip";
+    }
+    const parent = new Parent();
+    await parent.mount(fixture);
+
+    expect(fixture.innerHTML).toBe(
+      "<div><child><p>Ablip</p>default2<child>default1<p>Bblip</p></child></child></div>"
+    );
+  });
 });

tests/qweb/__snapshots__/qweb.test.ts.snap

@@ -431,8 +431,12 @@ exports[`foreach does not pollute the rendering context 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -466,8 +470,12 @@ exports[`foreach iterate on items (on a element node) 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -504,8 +512,12 @@ exports[`foreach iterate on items 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -551,8 +563,12 @@ exports[`foreach iterate, dict param 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -598,8 +614,12 @@ exports[`foreach iterate, position 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -643,8 +663,12 @@ exports[`foreach t-call with body in t-foreach in t-foreach 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -660,8 +684,12 @@ exports[`foreach t-call with body in t-foreach in t-foreach 1`] = `
         if (!_6) { throw new Error('QWeb error: Invalid loop expression')}
         let _7 = _8 = _6;
         if (!(_6 instanceof Array)) {
-            _7 = Object.keys(_6);
+            if (typeof _6[Symbol.iterator] === 'function') {
-            _8 = Object.values(_6);
+                _7 = [..._6];
+            } else {
+                _7 = Object.keys(_6);
+                _8 = Object.values(_6);
+            }
         }
         let _length7 = _7.length;
         let _origScope9 = scope;
@@ -731,8 +759,12 @@ exports[`foreach t-call without body in t-foreach in t-foreach 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -748,8 +780,12 @@ exports[`foreach t-call without body in t-foreach in t-foreach 1`] = `
         if (!_6) { throw new Error('QWeb error: Invalid loop expression')}
         let _7 = _8 = _6;
         if (!(_6 instanceof Array)) {
-            _7 = Object.keys(_6);
+            if (typeof _6[Symbol.iterator] === 'function') {
-            _8 = Object.values(_6);
+                _7 = [..._6];
+            } else {
+                _7 = Object.keys(_6);
+                _8 = Object.values(_6);
+            }
         }
         let _length7 = _7.length;
         let _origScope9 = scope;
@@ -813,8 +849,12 @@ exports[`foreach t-foreach in t-forach 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -830,8 +870,12 @@ exports[`foreach t-foreach in t-forach 1`] = `
         if (!_6) { throw new Error('QWeb error: Invalid loop expression')}
         let _7 = _8 = _6;
         if (!(_6 instanceof Array)) {
-            _7 = Object.keys(_6);
+            if (typeof _6[Symbol.iterator] === 'function') {
-            _8 = Object.values(_6);
+                _7 = [..._6];
+            } else {
+                _7 = Object.keys(_6);
+                _8 = Object.values(_6);
+            }
         }
         let _length7 = _7.length;
         let _origScope9 = scope;
@@ -861,6 +905,162 @@ exports[`foreach t-foreach in t-forach 1`] = `
 }"
 `;
 
+exports[`foreach t-foreach supports custom iterators 1`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"test\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    let _2 = scope['iterator'];
+    if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
+    let _3 = _4 = _2;
+    if (!(_2 instanceof Array)) {
+        if (typeof _2[Symbol.iterator] === 'function') {
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
+    }
+    let _length3 = _3.length;
+    let _origScope5 = scope;
+    scope = Object.create(scope);
+    for (let i1 = 0; i1 < _length3; i1++) {
+        scope.item_first = i1 === 0
+        scope.item_last = i1 === _length3 - 1
+        scope.item_index = i1
+        scope.item = _3[i1]
+        scope.item_value = _4[i1]
+        let key1 = i1;
+        let _6 = scope['item'];
+        if (_6 != null) {
+            c1.push({text: _6});
+        }
+    }
+    scope = _origScope5;
+    return vn1;
+}"
+`;
+
+exports[`foreach t-foreach supports custom iterators 2`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"test\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    let _2 = scope['iterator'];
+    if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
+    let _3 = _4 = _2;
+    if (!(_2 instanceof Array)) {
+        if (typeof _2[Symbol.iterator] === 'function') {
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
+    }
+    let _length3 = _3.length;
+    let _origScope5 = scope;
+    scope = Object.create(scope);
+    for (let i1 = 0; i1 < _length3; i1++) {
+        scope.item_first = i1 === 0
+        scope.item_last = i1 === _length3 - 1
+        scope.item_index = i1
+        scope.item = _3[i1]
+        scope.item_value = _4[i1]
+        let key1 = i1;
+        let _6 = scope['item'];
+        if (_6 != null) {
+            c1.push({text: _6});
+        }
+    }
+    scope = _origScope5;
+    return vn1;
+}"
+`;
+
+exports[`foreach t-foreach supports custom iterators 3`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"test\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    let _2 = scope['iterator'];
+    if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
+    let _3 = _4 = _2;
+    if (!(_2 instanceof Array)) {
+        if (typeof _2[Symbol.iterator] === 'function') {
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
+    }
+    let _length3 = _3.length;
+    let _origScope5 = scope;
+    scope = Object.create(scope);
+    for (let i1 = 0; i1 < _length3; i1++) {
+        scope.item_first = i1 === 0
+        scope.item_last = i1 === _length3 - 1
+        scope.item_index = i1
+        scope.item = _3[i1]
+        scope.item_value = _4[i1]
+        let key1 = i1;
+        let _6 = scope['item'];
+        if (_6 != null) {
+            c1.push({text: _6});
+        }
+    }
+    scope = _origScope5;
+    return vn1;
+}"
+`;
+
+exports[`foreach t-foreach supports custom iterators 4`] = `
+"function anonymous(context, extra
+) {
+    // Template name: \\"test\\"
+    let scope = Object.create(context);
+    let h = this.h;
+    let c1 = [], p1 = {key:1};
+    let vn1 = h('div', p1, c1);
+    let _2 = scope['iterator'];
+    if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
+    let _3 = _4 = _2;
+    if (!(_2 instanceof Array)) {
+        if (typeof _2[Symbol.iterator] === 'function') {
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
+    }
+    let _length3 = _3.length;
+    let _origScope5 = scope;
+    scope = Object.create(scope);
+    for (let i1 = 0; i1 < _length3; i1++) {
+        scope.item_first = i1 === 0
+        scope.item_last = i1 === _length3 - 1
+        scope.item_index = i1
+        scope.item = _3[i1]
+        scope.item_value = _4[i1]
+        let key1 = i1;
+        let _6 = scope['item'];
+        if (_6 != null) {
+            c1.push({text: _6});
+        }
+    }
+    scope = _origScope5;
+    return vn1;
+}"
+`;
+
 exports[`foreach warn if no key in some case 1`] = `
 "function anonymous(context, extra
 ) {
@@ -873,8 +1073,12 @@ exports[`foreach warn if no key in some case 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -942,8 +1146,12 @@ exports[`misc global 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -1509,8 +1717,12 @@ exports[`t-call (template calling recursive template, part 2 2`] = `
     if (!_5) { throw new Error('QWeb error: Invalid loop expression')}
     let _6 = _7 = _5;
     if (!(_5 instanceof Array)) {
-        _6 = Object.keys(_5);
+        if (typeof _5[Symbol.iterator] === 'function') {
-        _7 = Object.values(_5);
+            _6 = [..._5];
+        } else {
+            _6 = Object.keys(_5);
+            _7 = Object.values(_5);
+        }
     }
     let _length6 = _6.length;
     let _origScope8 = scope;
@@ -1588,8 +1800,12 @@ exports[`t-call (template calling recursive template, part 3 2`] = `
     if (!_5) { throw new Error('QWeb error: Invalid loop expression')}
     let _6 = _7 = _5;
     if (!(_5 instanceof Array)) {
-        _6 = Object.keys(_5);
+        if (typeof _5[Symbol.iterator] === 'function') {
-        _7 = Object.values(_5);
+            _6 = [..._5];
+        } else {
+            _6 = Object.keys(_5);
+            _7 = Object.values(_5);
+        }
     }
     let _length6 = _6.length;
     let _origScope8 = scope;
@@ -1673,8 +1889,12 @@ exports[`t-call (template calling recursive template, part 4: with t-set recursi
     if (!_5) { throw new Error('QWeb error: Invalid loop expression')}
     let _6 = _7 = _5;
     if (!(_5 instanceof Array)) {
-        _6 = Object.keys(_5);
+        if (typeof _5[Symbol.iterator] === 'function') {
-        _7 = Object.values(_5);
+            _6 = [..._5];
+        } else {
+            _6 = Object.keys(_5);
+            _7 = Object.values(_5);
+        }
     }
     let _length6 = _6.length;
     let _origScope8 = scope;
@@ -1810,8 +2030,12 @@ exports[`t-call (template calling t-call with t-set inside and outside 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -2587,8 +2811,12 @@ exports[`t-key t-key directive in a list 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -2691,8 +2919,12 @@ exports[`t-on can bind handlers with loop variable as argument 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -2973,8 +3205,12 @@ exports[`t-on t-on with prevent modifier in t-foreach 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -3227,8 +3463,12 @@ exports[`t-ref refs in a loop 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;
@@ -3471,8 +3711,12 @@ exports[`t-set t-set should reuse variable if possible 1`] = `
     if (!_2) { throw new Error('QWeb error: Invalid loop expression')}
     let _3 = _4 = _2;
     if (!(_2 instanceof Array)) {
-        _3 = Object.keys(_2);
+        if (typeof _2[Symbol.iterator] === 'function') {
-        _4 = Object.values(_2);
+            _3 = [..._2];
+        } else {
+            _3 = Object.keys(_2);
+            _4 = Object.values(_2);
+        }
     }
     let _length3 = _3.length;
     let _origScope5 = scope;

tests/qweb/qweb.test.ts

@@ -1263,6 +1263,44 @@ describe("foreach", () => {
     );
     console.warn = consoleWarn;
   });
+
+  test('t-foreach supports custom iterators', () => {
+    qweb.addTemplate(
+      "test",
+      `
+      <div>
+        <t t-foreach="iterator" t-as="item">
+          <t t-esc="item"/>
+        </t>
+    </div>`
+    );
+
+    let iterator: any = [1, 2, 3];
+    let result = trim(renderToString(qweb, "test", { iterator } ));
+    let expected = `<div>123</div>`;
+    expect(result).toBe(expected);
+    
+    iterator = { 1: 1, 2: 2, 3:3 };
+    result = trim(renderToString(qweb, "test", { iterator } ));
+    expected = `<div>123</div>`;
+    expect(result).toBe(expected);
+    
+    iterator = new Set([1, 2, 3]);
+    result = trim(renderToString(qweb, "test", { iterator } ));
+    expected = `<div>123</div>`;
+    expect(result).toBe(expected);
+      
+    iterator = {}
+    iterator[Symbol.iterator] = function* () {
+      yield 1;
+      yield 2;
+      yield 3;
+    }
+    result = trim(renderToString(qweb, "test", { iterator } ));
+    expected = `<div>123</div>`;
+    expect(result).toBe(expected);
+  });
+
 });
 
 describe("misc", () => {