add map, filter and text

Author: dealfonso

README.md

@@ -121,6 +121,11 @@ To solve the concept of the __context__ in calls to _jQuery_'s function `$`, __n
 - `get(index)`, that retrieves the object at position `index` in the collection.
 - `each(callback)`, that calls `callback` for each object in the collection.
     - callback is a function `callback(index, element)` that receives the index of the object in the collection and the object itself. The function is bound to the collection (so that `this` means the collection).
+- `map(callback)`, that calls `callback` for each object in the collection and returns the results in an array.
+    - callback is a function `callback(index, element)` that receives the index of the object in the collection and the object itself. The function is bound to the collection (so that `this` means the collection).
+- `filter(callback)`, that filters the objects in the collection by calling `callback` for each object in the collection.
+    - callback is a function `callback(index, element)` that receives the index of the object in the collection and the object itself. The function is bound to the collection (so that `this` means the collection). The function must return `true` to keep the object in the collection.
+- `text(text)`, that sets the text of the first object in the collection, or retrieves the text of the first object in the collection.
 
 These functions are enabled to the collections resulting of calls to `_$`.
 

dist/nojquery.js

@@ -330,6 +330,31 @@ SOFTWARE.
 			}
 			return this;
 		};
+		$.map = function (callback) {
+			let result = [];
+			callback = callback.bind(this);
+			for (let i = 0; i < this.length; i++) {
+				result.push(callback(i, this[i]));
+			}
+			return result;
+		};
+		$.filter = function (callback) {
+			let result = [];
+			callback = callback.bind(this);
+			for (let i = 0; i < this.length; i++) {
+				if (callback(i, this[i])) {
+					result.push(this[i]);
+				}
+			}
+			return $(result);
+		};
+		$.text = function (text) {
+			if (text === undefined) {
+				return this[0].innerText;
+			}
+			this.forEach(x => x.innerText = text);
+			return this;
+		};
 		$._$ = function (...elements) {
 			return $.bind(this)(...elements);
 		};

dist/nojquery.min.js

@@ -548,6 +548,56 @@
         return this;
     }
 
+    /**
+     * Function that calls a function for each element in the collection and returns an array with the
+     *   results of the calls to the function. The function will receive two parameters: callback(index, element)
+     *   where <index> is the index of the element in the collection and <element> is the element itself. The function
+     *   is bound to the collection, so that this[index] will be the element.
+     * @param {*} callback: the function to call for each element in the collection
+     * @returns an array with the results of the calls to the function
+     */
+    $.map = function(callback) {
+        let result = [];
+        callback = callback.bind(this);
+        for (let i = 0; i < this.length; i++) {
+            result.push(callback(i, this[i]));
+        }
+        return result;
+    }
+
+    /**
+     * Function that filters the elements in the collection that return "true"-ish when calling the callback function. 
+     *  The callback function will receive two parameters: callback(index, element) where <index> is the index of the 
+     *  element in the collection and <element> is the element itself. The function is bound to the collection, so that 
+     *  this[index] will be the element.
+     *  The callback function should return true if the element passes the filter, false otherwise.
+     * @param {*} callback: the function to filter the elements in the collection
+     * @returns a new collection with the elements that pass the filter
+     */
+    $.filter = function(callback) {
+        let result = [];
+        callback = callback.bind(this);
+        for (let i = 0; i < this.length; i++) {
+            if (callback(i, this[i])) {
+                result.push(this[i]);
+            }
+        }
+        return $(result);
+    }
+
+    /**
+     * Function that retrieves the text of the first element in the collection, or sets the text of all the elements
+     * @param {*} text: the text to set for the elements
+     * @returns the text of the first element in the collection or the collection of objects
+     */
+    $.text = function(text) {
+        if (text === undefined) {
+            return this[0].innerText;
+        }
+        this.forEach((x) => x.innerText = text);
+        return this;
+    }
+    
     /**
      * The $ function scoped to the objects that are part of a previous $ object; this is the same
      *      function $(...elements), except for the fact that the search for elements using selectors