Add support for minLength option

src/dataset.js

@@ -19,6 +19,7 @@ var Dataset = (function() {
 
     this.name = o.name || utils.getUniqueId();
     this.limit = o.limit || 5;
+    this.minLength = o.minLength || 1;
     this.header = o.header;
     this.footer = o.footer;
     this.valueKey = o.valueKey || 'value';
@@ -246,9 +247,15 @@ var Dataset = (function() {
     },
 
     getSuggestions: function(query, cb) {
-      var that = this,
-          terms = utils.tokenizeQuery(query),
-          suggestions = this._getLocalSuggestions(terms).slice(0, this.limit);
+      var that = this, terms, suggestions;
+
+      // don't do anything until the minLength constraint is met
+      if (query.length < this.minLength) {
+        return;
+      }
+
+      terms = utils.tokenizeQuery(query);
+      suggestions = this._getLocalSuggestions(terms).slice(0, this.limit);
 
       cb && cb(suggestions);
 

test/dataset_spec.js

@@ -288,6 +288,22 @@ describe('Dataset', function() {
     });
   });
 
+  describe('#getSuggestions', function() {
+    describe('when length of query is less than minLength', function() {
+      beforeEach(function() {
+        this.spy = jasmine.createSpy();
+
+        this.dataset = new Dataset({ local: fixtureStrings, minLength: 3 });
+        this.dataset.initialize();
+      });
+
+      it('should be a noop', function() {
+        this.dataset.getSuggestions('co', this.spy);
+        expect(this.spy).not.toHaveBeenCalled();
+      });
+    });
+  });
+
   describe('Matching, combining, returning results', function() {
     beforeEach(function() {
       this.dataset = new Dataset({ local: fixtureStrings, remote: '/remote' });

test/playground.html

@@ -52,6 +52,7 @@
     <script>
       $('.states').typeahead({
         valueKey: 'state',
+        minLength: 3,
         local: [
           "Alabama",
           "Alaska",