Merge pull request #236 from cupofjoakim/master

Rule for throttle

README.md

@@ -142,6 +142,7 @@ then Lodash/Underscore is the better option.*
 1. [_.bind](#_bind)
 1. [_.debounce](#_debounce)
 1. [_.partial](#_partial)
+1. [_.throttle](#_throttle)
 
 **[Lang](#lang)**
 
@@ -1647,7 +1648,7 @@ Create a new function that calls _func_ with _thisArg_ and _args_.
 
  **[⬆ back to top](#quick-links)**
  
- ### _.debounce
+### _.debounce
 Create a new function that calls _func_ with _thisArg_ and _args_.
 
   ```js
@@ -1715,6 +1716,35 @@ Create a new function that calls _func_ with _args_.
 
 **[⬆ back to top](#quick-links)**
 
+
+### _.throttle
+Create a new function that limits calls to _func_ to once every given timeframe.
+
+  ```js
+  function throttle(func, timeFrame) {
+    var lastTime = 0;
+    return function () {
+        var now = new Date();
+        if (now - lastTime >= timeFrame) {
+            func();
+            lastTime = now;
+        }
+    };
+  }
+
+  // Avoid running the same function twice within the specified timeframe.
+  jQuery(window).on('resize', throttle(calculateLayout, 150));
+
+  ```
+#### Browser Support for `throttle`
+
+![Chrome][chrome-image] | ![Edge][edge-image] | ![Firefox][firefox-image] | ![IE][ie-image] | ![Opera][opera-image] | ![Safari][safari-image]
+ :-: | :-: | :-: | :-: | :-: | :-: |
+  5.0 ✔  |  12.0 ✔ | 3.0 ✔ |  9.0 ✔ |  10.5 ✔ |  4.0 ✔  |
+
+ **[⬆ back to top](#quick-links)**
+ 
+
 ## Lang
 
 ### _.gt

lib/rules/rules.json

@@ -272,5 +272,9 @@
     "flatten": {
     	"compatible": true,
     	"alternative": "Array.prototype.reduce((a,b) => a.concat(b), [])"
+    },
+    "throttle": {
+        "compatible": true,
+        "alternative": "Example of native implementation: https://github.com/you-dont-need/You-Dont-Need-Lodash-Underscore#_throttle"
     }
 }

tests/unit/all.js

@@ -729,4 +729,28 @@ describe('code snippet example', () => {
       );
     });
   });
+
+  describe('throttle', () => {
+    function throttle(func, timeFrame) {
+      var lastTime = 0;
+      return function () {
+        var now = new Date();
+        if (now - lastTime >= timeFrame) {
+          func();
+          lastTime = now;
+        }
+      };
+    }
+
+    it('throttle is not called more than once within timeframe', () => {
+      let callCount = 0;
+      const fn = throttle(() => callCount++, 100);
+
+      fn();
+      fn();
+      fn();
+
+      assert.equal(callCount, 1);
+    });
+  })
 });