Support Map and Set in #each block

lib/handlebars/helpers/each.js

@@ -1,5 +1,5 @@
 import { Exception } from '@handlebars/parser';
-import { createFrame, isArray, isFunction } from '../utils';
+import { createFrame, isArray, isFunction, isMap, isSet } from '../utils';
 
 export default function (instance) {
   instance.registerHelper('each', function (context, options) {
@@ -21,7 +21,7 @@ export default function (instance) {
       data = createFrame(options.data);
     }
 
-    function execIteration(field, index, last) {
+    function execIteration(field, value, index, last) {
       if (data) {
         data.key = field;
         data.index = index;
@@ -31,7 +31,7 @@ export default function (instance) {
 
       ret =
         ret +
-        fn(context[field], {
+        fn(value, {
           data: data,
           blockParams: [context[field], field],
         });
@@ -41,9 +41,19 @@ export default function (instance) {
       if (isArray(context)) {
         for (let j = context.length; i < j; i++) {
           if (i in context) {
-            execIteration(i, i, i === context.length - 1);
+            execIteration(i, context[i], i, i === context.length - 1);
           }
         }
+      } else if (isMap(context)) {
+        const j = context.size;
+        for (const [key, value] of context) {
+          execIteration(key, value, i++, i === j);
+        }
+      } else if (isSet(context)) {
+        const j = context.size;
+        for (const value of context) {
+          execIteration(i, value, i++, i === j);
+        }
       } else if (typeof Symbol === 'function' && context[Symbol.iterator]) {
         const newContext = [];
         const iterator = context[Symbol.iterator]();
@@ -52,7 +62,7 @@ export default function (instance) {
         }
         context = newContext;
         for (let j = context.length; i < j; i++) {
-          execIteration(i, i, i === context.length - 1);
+          execIteration(i, context[i], i, i === context.length - 1);
         }
       } else {
         let priorKey;
@@ -62,13 +72,13 @@ export default function (instance) {
           // the last iteration without have to scan the object twice and create
           // an intermediate keys array.
           if (priorKey !== undefined) {
-            execIteration(priorKey, i - 1);
+            execIteration(priorKey, context[priorKey], i - 1);
           }
           priorKey = key;
           i++;
         });
         if (priorKey !== undefined) {
-          execIteration(priorKey, i - 1, true);
+          execIteration(priorKey, context[priorKey], i - 1, true);
         }
       }
     }

lib/handlebars/runtime.js

@@ -124,6 +124,10 @@ export function template(templateSpec, env) {
       return container.lookupProperty(obj, name);
     },
     lookupProperty: function (parent, propertyName) {
+      if (Utils.isMap(parent)) {
+        return parent.get(propertyName);
+      }
+
       let result = parent[propertyName];
       if (result == null) {
         return result;

lib/handlebars/utils.js

@@ -35,14 +35,18 @@ export function isFunction(value) {
   return typeof value === 'function';
 }
 
-/* istanbul ignore next */
-export const isArray =
-  Array.isArray ||
-  function (value) {
+function testTag(name) {
+  const tag = '[object ' + name + ']';
+  return function (value) {
     return value && typeof value === 'object'
-      ? toString.call(value) === '[object Array]'
+      ? toString.call(value) === tag
       : false;
   };
+}
+
+export const isArray = Array.isArray;
+export const isMap = testTag('Map');
+export const isSet = testTag('Set');
 
 // Older IE versions do not directly support indexOf so we must implement our own, sadly.
 export function indexOf(array, value) {

spec/basic.js

@@ -387,6 +387,13 @@ describe('basic context', function () {
       .toCompileTo('Goodbye beautiful world!');
   });
 
+  it('nested paths with Map', function () {
+    expectTemplate('Goodbye {{alan/expression}} world!')
+      .withInput({ alan: new Map([['expression', 'beautiful']]) })
+      .withMessage('Nested paths access nested objects')
+      .toCompileTo('Goodbye beautiful world!');
+  });
+
   it('nested paths with empty string value', function () {
     expectTemplate('Goodbye {{alan/expression}} world!')
       .withInput({ alan: { expression: '' } })

spec/builtins.js

@@ -508,6 +508,50 @@ describe('builtin helpers', function () {
       );
     });
 
+    it('each on Map', function () {
+      var map = new Map([
+        [1, 'one'],
+        [2, 'two'],
+        [3, 'three'],
+      ]);
+
+      expectTemplate('{{#each map}}{{@key}}(i{{@index}}) {{.}} {{/each}}')
+        .withInput({ map: map })
+        .toCompileTo('1(i0) one 2(i1) two 3(i2) three ');
+
+      expectTemplate('{{#each map}}{{#if @first}}{{.}}{{/if}}{{/each}}')
+        .withInput({ map: map })
+        .toCompileTo('one');
+
+      expectTemplate('{{#each map}}{{#if @last}}{{.}}{{/if}}{{/each}}')
+        .withInput({ map: map })
+        .toCompileTo('three');
+
+      expectTemplate('{{#each map}}{{.}}{{/each}}not-in-each')
+        .withInput({ map: new Map() })
+        .toCompileTo('not-in-each');
+    });
+
+    it('each on Set', function () {
+      var set = new Set([1, 2, 3]);
+
+      expectTemplate('{{#each set}}{{@key}}(i{{@index}}) {{.}} {{/each}}')
+        .withInput({ set: set })
+        .toCompileTo('0(i0) 1 1(i1) 2 2(i2) 3 ');
+
+      expectTemplate('{{#each set}}{{#if @first}}{{.}}{{/if}}{{/each}}')
+        .withInput({ set: set })
+        .toCompileTo('1');
+
+      expectTemplate('{{#each set}}{{#if @last}}{{.}}{{/if}}{{/each}}')
+        .withInput({ set: set })
+        .toCompileTo('3');
+
+      expectTemplate('{{#each set}}{{.}}{{/each}}not-in-each')
+        .withInput({ set: new Set() })
+        .toCompileTo('not-in-each');
+    });
+
     if (global.Symbol && global.Symbol.iterator) {
       it('each on iterable', function () {
         function Iterator(arr) {

spec/utils.js

@@ -86,4 +86,21 @@ describe('utils', function () {
       equals(b.b, 2);
     });
   });
+
+  describe('#isType', function () {
+    it('should check if variable is type Array', function () {
+      expect(Handlebars.Utils.isArray('string')).to.equal(false);
+      expect(Handlebars.Utils.isArray([])).to.equal(true);
+    });
+
+    it('should check if variable is type Map', function () {
+      expect(Handlebars.Utils.isMap('string')).to.equal(false);
+      expect(Handlebars.Utils.isMap(new Map())).to.equal(true);
+    });
+
+    it('should check if variable is type Set', function () {
+      expect(Handlebars.Utils.isSet('string')).to.equal(false);
+      expect(Handlebars.Utils.isSet(new Set())).to.equal(true);
+    });
+  });
 });

types/index.d.ts

@@ -123,6 +123,8 @@ declare namespace Handlebars {
       export function toString(obj: any): string;
       export function isArray(obj: any): boolean;
       export function isFunction(obj: any): boolean;
+      export function isMap(obj: any): boolean;
+      export function isSet(obj: any): boolean;
   }
 
   export namespace AST {