buster.filter

lib/buster-core.js

@@ -182,6 +182,32 @@ var buster = (function (setTimeout, B) {
         };
     }
 
+    if (Array.prototype.filter) {
+        buster.filter = function (arr, fn, thisp) {
+            return arr.filter(fn, thisp);
+        };
+    } else {
+        // https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/filter
+        buster.filter = function (fn, thisp) {
+            "use strict";
+            if (this == null) { throw new TypeError(); }
+
+            var t = Object(this);
+            var len = t.length >>> 0;
+            if (typeof fn != "function") { throw new TypeError(); }
+
+            var res = [];
+            for (var i = 0; i < len; i++) {
+                if (i in t) {
+                    var val = t[i]; // in case fun mutates this
+                    if (fn.call(thisp, val, i, t)) { res.push(val); }
+                }
+            }
+
+            return res;
+        };
+    }
+
     if (isNode) {
         module.exports = buster;
         buster.eventEmitter = require("./buster-event-emitter");

test/buster-core-test.js

@@ -246,6 +246,15 @@
         }
     });
 
+    bu.testCase("BusterFilterTest", {
+        "should filter items": function () {
+            function isBigEnough(element) { return (element >= 10); }
+            var filtered = B.filter([12, 5, 8, 130, 44], isBigEnough);
+
+            assert.deepEqual(filtered, [12, 130, 44]);
+        }
+    });
+
     bu.testCase("BusterParallelTest", {
         setUp: function () {
             this.fns = [sinon.stub(), sinon.stub(), sinon.stub()];