wink-helpers - npm Package Compare versions

Comparing version 1.0.1 to 1.1.0

package.json

 {
   "name": "wink-helpers",
-  "version": "1.0.1",
+  "version": "1.1.0",
   "description": "Low level helper functions for Javascript arrays and objects",
@@ -5,0 +5,0 @@ "keywords": [

README.md

@@ -42,2 +42,5 @@
 // -> [ { "name": "marry", "age": 37 }, { "name": "john", "age": 42 } ]
+
+console.log( helpers.array.product( [ [ 9, 8 ], [ 1, 2 ] ] ) );
+// -> [ [ 9, 1 ], [ 9, 2 ], [ 8, 1 ], [ 8, 2 ] ]
 ```
@@ -72,2 +75,15 @@
 
+#### product( array )
+Returns the *cartesian product* of the arrays present inside the `array` argument. For example, if the `array` argument is `[ [ 1, 2, 3 ], [ 4 ], [ 5, 6 ] ]`, then the return value will be:
+```javascript
+[
+  [ 1, 4, 5 ],
+  [ 1, 4, 6 ],
+  [ 2, 4, 5 ],
+  [ 2, 4, 6 ],
+  [ 3, 4, 5 ],
+  [ 3, 4, 6 ]
+]
+```
+
 ### object
@@ -74,0 +90,0 @@

src/wink-helpers.js

@@ -27,2 +27,25 @@ //     wink-helpers
 
+// ### Private Functions
+
+// #### Product Reducer (Callback)
+
+// Callback function used by `reduce` inside the `product()` function.
+// Follows the standard guidelines of `reduce()` callback function.
+var productReducer = function ( prev, curr ) {
+  var c,
+      cmax = curr.length;
+  var p,
+      pmax = prev.length;
+  var result = [];
+
+  for ( p = 0; p < pmax; p += 1 ) {
+    for ( c = 0; c < cmax; c += 1 ) {
+      result.push( prev[ p ].concat( curr[ c ] ) );
+    }
+  }
+  return ( result );
+}; // productReducer()
+
+// ### Public Function
+
 // ### Array Helpers
@@ -120,3 +143,15 @@
 
+// #### product
 
+// Finds the Cartesian Product of arrays present inside the array `a`. Therefore
+// the array `a` must be an array of 1-dimensional arrays. For example,
+// `product( [ [ 9, 8 ], [ 1, 2 ] ] )`
+// will produce `[ [ 9, 1 ], [ 9, 2 ], [ 8, 1 ], [ 8, 2 ] ]`.
+helpers.array.product = function ( a ) {
+  return (
+    a.reduce( productReducer, [ [] ] )
+  );
+};
+
+
 // ### Object Helpers
@@ -123,0 +158,0 @@

test/wink-helpers-specs.js

@@ -176,2 +176,43 @@ //     wink-helpers
 
+describe( 'cartesian product', function () {
+  var expectedOutputIs = [
+        [ [ 9, 1 ], [ 9, 2 ], [ 8, 1 ], [ 8, 2 ] ],
+        [ ],
+        [
+          [ 1, 4, 5 ],
+          [ 1, 4, 6 ],
+          [ 2, 4, 5 ],
+          [ 2, 4, 6 ],
+          [ 3, 4, 5 ],
+          [ 3, 4, 6 ]
+        ],
+        [
+          [ 1, 4, 6 ],
+          [ 1, 4, 7 ],
+          [ 1, 5, 6 ],
+          [ 1, 5, 7 ],
+          [ 2, 4, 6 ],
+          [ 2, 4, 7 ],
+          [ 2, 5, 6 ],
+          [ 2, 5, 7 ],
+          [ 3, 4, 6 ],
+          [ 3, 4, 7 ],
+          [ 3, 5, 6 ],
+          [ 3, 5, 7 ]
+        ]
+      ],
+      whenInputIs = [
+        [ [ 9, 8 ], [ 1, 2 ] ],
+        [ [ 9, 8 ], [ 1, 2 ], [ ] ],
+        [ [ 1, 2, 3 ], [ 4 ], [ 5, 6 ] ],
+        [ [ 1, 2, 3 ], [ 4, 5 ], [ 6, 7 ] ]
+      ];
+
+  whenInputIs.forEach( function ( input, i ) {
+    it( 'should return ' + JSON.stringify( expectedOutputIs[ i ] ) + '\n\tif the input is ' + JSON.stringify( input ), function () {
+      expect(  helpers.array.product( input ) ).to.deep.equal( expectedOutputIs[ i ] );
+    } );
+  } );
+} );
+
 describe( 'isObject', function () {
@@ -178,0 +219,0 @@ var tests = [

No alert changes

Improved metrics

Total package byte prevSize

69694

increased by3.61%

Lines of code

730

increased by10.11%

Number of lines in readme file

117

increased by15.84%

No dependency changes