Add support for arrow functions to map filter.

Author: antoineveldhoven

src/twig.filters.js

@@ -846,6 +846,25 @@ module.exports = function (Twig) {
                     return template.render(data) === 'true';
                 });
             }
+        },
+        map(value, params) {
+            if (is('Array', value)) {
+                const callBackParams = params.params.split(',');
+                // Since Javascript does not support a callBack function to map() with both keys and values; we use forEach here
+                // Note: Twig and PHP use ((value[, key])) for map(); whereas Javascript uses (([key, ]value)) for forEach()
+                const newValue = [];
+                value.forEach((_b, _a) => {
+                    const data = {};
+                    data[callBackParams[0]] = _b;
+                    if (callBackParams[1]) {
+                        data[callBackParams[1]] = _a;
+                    }
+
+                    const template = Twig.exports.twig({data: params.body});
+                    newValue[_a] = template.render(data);
+                });
+                return newValue;
+            }
         }
     };
 

test/test.filters.js

@@ -871,6 +871,13 @@ describe('Twig.js Filters ->', function () {
         });
     });
 
+    describe('map ->', function () {
+        it('should map an array (with keys)', function () {
+            let testTemplate = twig({data: '{{ [1,5,2,7,8]|map((v) => v*v) }}'});
+            testTemplate.render().should.equal('1,25,4,49,64');
+        });
+    });
+
     it('should chain', function () {
         const testTemplate = twig({data: '{{ ["a", "b", "c"]|keys|reverse }}'});
         testTemplate.render().should.equal('2,1,0');