adds .union method. resolves #3

Author: jonschlinkert

index.js

@@ -86,6 +86,29 @@ function namespace(prop) {
     return this;
   };
 
+  /**
+   * Union `array` to `key`. Also emits `set` with
+   * the key and value.
+   *
+   * ```js
+   * app.union('a.b', ['foo']);
+   * app.union('a.b', ['bar']);
+   * console.log(app.get('a'));
+   * //=> {b: ['foo', 'bar']}
+   * ```
+   * @name .union
+   * @param {String} `key`
+   * @param {any} `value`
+   * @return {Object} Returns the instance for chaining.
+   * @api public
+   */
+
+  Cache.prototype.union = function(key, val) {
+    var ctx = prop ? this[prop] : this;
+    utils.union(ctx, key, utils.arrayify(val));
+    return this;
+  };
+
   /**
    * Return the value of `key`. Dot notation may be used
    * to get [nested property values][get-value].

package.json

@@ -1,7 +1,7 @@
 {
   "name": "cache-base",
   "description": "Basic object cache with `get`, `set`, `del`, and `has` methods for node.js/javascript projects.",
-  "version": "0.8.2",
+  "version": "0.8.3",
   "homepage": "https://github.com/jonschlinkert/cache-base",
   "author": "Jon Schlinkert (https://github.com/jonschlinkert)",
   "repository": "jonschlinkert/cache-base",
@@ -22,18 +22,19 @@
   },
   "dependencies": {
     "collection-visit": "^0.2.1",
-    "component-emitter": "^1.2.0",
-    "get-value": "^2.0.3",
-    "has-value": "^0.3.0",
+    "component-emitter": "^1.2.1",
+    "get-value": "^2.0.5",
+    "has-value": "^0.3.1",
     "isobject": "^2.0.0",
     "lazy-cache": "^1.0.3",
     "set-value": "^0.3.3",
     "to-object-path": "^0.3.0",
+    "union-value": "^0.2.3",
     "unset-value": "^0.1.1"
   },
   "devDependencies": {
-    "gulp-format-md": "^0.1.7",
-    "mocha": "*"
+    "gulp-format-md": "^0.1.8",
+    "mocha": "^2.4.5"
   },
   "keywords": [
     "cache",

test/test.js

@@ -64,6 +64,41 @@ describe('cache-base', function() {
     });
   });
 
+  describe('.union()', function() {
+    it('should union a string value', function() {
+      app.union('a', 'b');
+      assert.deepEqual(app.get('a'), ['b']);
+    });
+
+    it('should union multiple string values', function() {
+      app.union('a', 'b');
+      app.union('a', 'c');
+      app.union('a', 'd');
+      assert.deepEqual(app.get('a'), ['b', 'c', 'd']);
+    });
+
+    it('should union multiple arrays', function() {
+      app.union('a', ['b']);
+      app.union('a', ['c']);
+      app.union('a', ['d']);
+      assert.deepEqual(app.get('a'), ['b', 'c', 'd']);
+    });
+
+    it('should union nested string values', function() {
+      app.union('a.b', 'b');
+      app.union('a.b', 'c');
+      app.union('a.b', 'd');
+      assert.deepEqual(app.get('a'), {b: ['b', 'c', 'd']});
+    });
+
+    it('should union and uniquify arrays', function() {
+      app.union('a.b', ['b', 'foo']);
+      app.union('a.b', ['c', 'foo']);
+      app.union('a.b', ['d', 'foo']);
+      assert.deepEqual(app.get('a'), {b: ['b', 'foo', 'c', 'd']});
+    });
+  });
+
   describe('.set()', function() {
     it('should set a value', function() {
       app.set('a', 'b');

utils.js

@@ -19,9 +19,18 @@ require('unset-value', 'del');
 require('get-value', 'get');
 require('has-value', 'has');
 require('set-value', 'set');
+require('union-value', 'union');
 require('to-object-path', 'toPath');
 require = fn;
 
+/**
+ * Cast val to an array
+ */
+
+utils.arrayify = function(val) {
+  return val ? (Array.isArray(val) ? val : [val]) : [];
+};
+
 /**
  * Expose `utils` modules
  */