[NEW] ArrayExt: pluck, sortBy

lib/array-ext.js

@@ -62,6 +62,22 @@ var ArrayExt = exports.ArrayExt = {
     // pack
     // partition
 
+  , pluck: function(a, /* key paths, ... */) {
+        var args = [].slice.call(arguments, 1);
+        args.unshift(a);
+        return pluck.apply(null, args);
+    }
+
+  , sortBy: function(arr, keyPath) {
+        return arr.slice().sort(function(a, b) {
+            var propA = drillInto(a)
+              , propB = drillInto(b);
+            if (propA < propB) return -1
+            if (propA > propB) return 1
+            return 0
+        });
+    }
+
   , toString: function(a) {
         return '[' + ArrayToString.call(a) + ']';
     }
@@ -77,3 +93,34 @@ var ArrayExt = exports.ArrayExt = {
         return b;
     }
 };
+
+
+// pluck
+
+function getProp(thing, key) {
+    if (thing === null || thing === undefined) return thing
+    var prop = thing[key]
+    return typeof prop === 'function' ? prop.call(thing) : prop
+}
+
+function drillInto(thing, keyPath) {
+    return keyPath.split('.').reduce(function(memo, key) {
+        return getProp(memo, key)
+    }, thing)
+}
+
+function mapInto(thing /* , key paths, ... */) {
+    var keyPaths = [].slice.call(arguments, 1)
+    return keyPaths.map(function(keyPath) {
+        return drillInto(thing, keyPath)
+    })
+}
+
+function pluck(things /* , key paths, ... */) {
+    var keyPaths = [].slice.call(arguments, 1)
+    return things.map(function(thing) {
+        var results = mapInto.apply(null, [thing].concat(keyPaths))
+        if (results.length > 1) return results
+        return results[0]
+    })
+}