[IMP] runtime: add support for Map and other iterables in t-foreach

closes: #1352

doc/reference/templates.md

@@ -376,15 +376,16 @@ An important difference should be made with the usual `QWeb` behaviour: Owl
 requires the presence of a `t-key` directive, to be able to properly reconcile
 renderings.
 
-`t-foreach` can iterate on an array (the current item will be the current value)
-or an object (the current item will be the current key).
+`t-foreach` can iterate on any iterable, and also has special support for objects
+and maps, it will expose the key of the current iteration as the contents of the
+`t-as`, and the corresponding value with the same name and the suffix `_value`.
 
-In addition to the name passed via t-as, `t-foreach` provides a few other
-variables for various data points (note: `$as` will be replaced with the name
-passed to `t-as`):
+In addition to the name passed via t-as, `t-foreach` provides a few other useful
+variables (note: `$as` will be replaced with the name passed to `t-as`):
 
-- `$as_value`: the current iteration value, identical to `$as` for lists and
-  integers, but for objects, it provides the value (where `$as` provides the key)
+- `$as_value`: the current iteration value, identical to `$as` for arrays and
+  other iterables, but for objects and maps, it provides the value (where `$as`
+  provides the key)
 - `$as_index`: the current iteration index (the first item of the iteration has index 0)
 - `$as_first`: whether the current item is the first of the iteration
   (equivalent to `$as_index == 0`)

src/runtime/template_helpers.ts

@@ -60,18 +60,26 @@ function withKey(elem: any, k: string) {
   return elem;
 }
 
-function prepareList(collection: any): [any[], any[], number, any[]] {
-  let keys: any[];
-  let values: any[];
+function prepareList(collection: unknown): [unknown[], unknown[], number, undefined[]] {
+  let keys: unknown[];
+  let values: unknown[];
 
   if (Array.isArray(collection)) {
     keys = collection;
     values = collection;
-  } else if (collection) {
-    values = Object.keys(collection);
-    keys = Object.values(collection);
+  } else if (collection instanceof Map) {
+    keys = [...collection.keys()];
+    values = [...collection.values()];
+  } else if (collection && typeof collection === "object") {
+    if (Symbol.iterator in collection) {
+      keys = [...(<Iterable<unknown>>collection)];
+      values = keys;
+    } else {
+      values = Object.keys(collection);
+      keys = Object.values(collection);
+    }
   } else {
-    throw new OwlError("Invalid loop expression");
+    throw new OwlError(`Invalid loop expression: "${collection}" is not iterable`);
   }
   const n = values.length;
   return [keys, values, n, new Array(n)];

tests/compiler/__snapshots__/t_foreach.test.ts.snap

@@ -77,6 +77,62 @@ exports[`t-foreach iterate on items 1`] = `
 }"
 `;
 
+exports[`t-foreach iterate, Map param 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, withKey } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    const [k_block1, v_block1, l_block1, c_block1] = prepareList(ctx['value']);;
+    for (let i1 = 0; i1 < l_block1; i1++) {
+      ctx[\`item\`] = v_block1[i1];
+      ctx[\`item_index\`] = i1;
+      ctx[\`item_value\`] = k_block1[i1];
+      const key1 = ctx['item_index'];
+      const b3 = text(\` [\`);
+      const b4 = text(ctx['item_index']);
+      const b5 = text(\`: \`);
+      const b6 = text(ctx['item']);
+      const b7 = text(\` \`);
+      const b8 = text(ctx['item_value']);
+      const b9 = text(\`] \`);
+      c_block1[i1] = withKey(multi([b3, b4, b5, b6, b7, b8, b9]), key1);
+    }
+    return list(c_block1);
+  }
+}"
+`;
+
+exports[`t-foreach iterate, Set param 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, withKey } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    const [k_block1, v_block1, l_block1, c_block1] = prepareList(ctx['value']);;
+    for (let i1 = 0; i1 < l_block1; i1++) {
+      ctx[\`item\`] = v_block1[i1];
+      ctx[\`item_index\`] = i1;
+      ctx[\`item_value\`] = k_block1[i1];
+      const key1 = ctx['item_index'];
+      const b3 = text(\` [\`);
+      const b4 = text(ctx['item_index']);
+      const b5 = text(\`: \`);
+      const b6 = text(ctx['item']);
+      const b7 = text(\` \`);
+      const b8 = text(ctx['item_value']);
+      const b9 = text(\`] \`);
+      c_block1[i1] = withKey(multi([b3, b4, b5, b6, b7, b8, b9]), key1);
+    }
+    return list(c_block1);
+  }
+}"
+`;
+
 exports[`t-foreach iterate, dict param 1`] = `
 "function anonymous(app, bdom, helpers
 ) {
@@ -108,6 +164,62 @@ exports[`t-foreach iterate, dict param 1`] = `
 }"
 `;
 
+exports[`t-foreach iterate, generator param 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, withKey } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    const [k_block1, v_block1, l_block1, c_block1] = prepareList(ctx['gen']());;
+    for (let i1 = 0; i1 < l_block1; i1++) {
+      ctx[\`item\`] = v_block1[i1];
+      ctx[\`item_index\`] = i1;
+      ctx[\`item_value\`] = k_block1[i1];
+      const key1 = ctx['item_index'];
+      const b3 = text(\` [\`);
+      const b4 = text(ctx['item_index']);
+      const b5 = text(\`: \`);
+      const b6 = text(ctx['item']);
+      const b7 = text(\` \`);
+      const b8 = text(ctx['item_value']);
+      const b9 = text(\`] \`);
+      c_block1[i1] = withKey(multi([b3, b4, b5, b6, b7, b8, b9]), key1);
+    }
+    return list(c_block1);
+  }
+}"
+`;
+
+exports[`t-foreach iterate, iterable param 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, withKey } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    const [k_block1, v_block1, l_block1, c_block1] = prepareList(ctx['map'].values());;
+    for (let i1 = 0; i1 < l_block1; i1++) {
+      ctx[\`item\`] = v_block1[i1];
+      ctx[\`item_index\`] = i1;
+      ctx[\`item_value\`] = k_block1[i1];
+      const key1 = ctx['item_index'];
+      const b3 = text(\` [\`);
+      const b4 = text(ctx['item_index']);
+      const b5 = text(\`: \`);
+      const b6 = text(ctx['item']);
+      const b7 = text(\` \`);
+      const b8 = text(ctx['item_value']);
+      const b9 = text(\`] \`);
+      c_block1[i1] = withKey(multi([b3, b4, b5, b6, b7, b8, b9]), key1);
+    }
+    return list(c_block1);
+  }
+}"
+`;
+
 exports[`t-foreach iterate, position 1`] = `
 "function anonymous(app, bdom, helpers
 ) {

tests/compiler/t_foreach.test.ts

@@ -105,6 +105,64 @@ describe("t-foreach", () => {
     expect(renderToString(template, context)).toBe(expected);
   });
 
+  test("iterate, Map param", () => {
+    const template = `
+      <t t-foreach="value" t-as="item" t-key="item_index">
+        [<t t-esc="item_index"/>: <t t-esc="item"/> <t t-esc="item_value"/>]
+      </t>`;
+    const expected = ` [0: 1 a]  [1: 2 b]  [2: 3 c] `;
+    const context = {
+      value: new Map([
+        ["a", 1],
+        ["b", 2],
+        ["c", 3],
+      ]),
+    };
+    expect(renderToString(template, context)).toBe(expected);
+  });
+
+  test("iterate, Set param", () => {
+    const template = `
+      <t t-foreach="value" t-as="item" t-key="item_index">
+        [<t t-esc="item_index"/>: <t t-esc="item"/> <t t-esc="item_value"/>]
+      </t>`;
+    const expected = ` [0: 1 1]  [1: 2 2]  [2: 3 3] `;
+    const context = { value: new Set([1, 2, 3]) };
+    expect(renderToString(template, context)).toBe(expected);
+  });
+
+  test("iterate, iterable param", () => {
+    const template = `
+      <t t-foreach="map.values()" t-as="item" t-key="item_index">
+        [<t t-esc="item_index"/>: <t t-esc="item"/> <t t-esc="item_value"/>]
+      </t>`;
+    const expected = ` [0: 1 1]  [1: 2 2]  [2: 3 3] `;
+    const context = {
+      map: new Map([
+        ["a", 1],
+        ["b", 2],
+        ["c", 3],
+      ]),
+    };
+    expect(renderToString(template, context)).toBe(expected);
+  });
+
+  test("iterate, generator param", () => {
+    const template = `
+      <t t-foreach="gen()" t-as="item" t-key="item_index">
+        [<t t-esc="item_index"/>: <t t-esc="item"/> <t t-esc="item_value"/>]
+      </t>`;
+    const expected = ` [0: 1 1]  [1: 2 2]  [2: 3 3] `;
+    const context = {
+      *gen() {
+        yield 1;
+        yield 2;
+        yield 3;
+      },
+    };
+    expect(renderToString(template, context)).toBe(expected);
+  });
+
   test("does not pollute the rendering context", () => {
     const template = `
         <div>
@@ -193,7 +251,9 @@ describe("t-foreach", () => {
 
   test("throws error if invalid loop expression", () => {
     const test = `<div><t t-foreach="abc" t-as="item" t-key="item"><span t-key="item_index"/></t></div>`;
-    expect(() => renderToString(test)).toThrow("Invalid loop expression");
+    expect(() => renderToString(test)).toThrow(
+      'Invalid loop expression: "undefined" is not iterable'
+    );
   });
 
   test("t-foreach with t-if inside", () => {