Merge pull request #753 from 30-seconds/feature/shank

[FEATURE] shank()

snippet_data/snippets.json

@@ -5186,6 +5186,17 @@
         "hash": "a5a49641c0de1a0a80f192c5be195c448ab0fe0856bba4e1f246fe70af7b5431"
       }
     },
+    {
+      "id": "shank",
+      "type": "snippet",
+      "attributes": {
+        "fileName": "shank.md",
+        "text": "Duplicates Array.prototype.splice, except it returns a new array rather than mutating the original array in place.",
+        "tags": [
+          "array"
+        ]
+      },
+    },
     {
       "id": "show",
       "type": "snippet",

snippets/shank.md

@@ -0,0 +1,23 @@
+### shank
+
+Has the same functionality as [`Array.prototype.splice()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice), but returning a new array instead of mutating the original array.
+
+Use `Array.slice()` and `Array.concat()` to get a new array with the new contents after removing existing elements and/or adding new elements.
+Omit the second argument, `index`, to start at `0`.
+Omit the third argument, `delCount`, to remove `0` elements.
+Omit the fourth argument, `elements`, in order to not add any new elements.
+
+```js
+const shank = (arr, index = 0, delCount = 0, ...elements) => 
+  arr.slice(0, index)
+     .concat(elements)
+     .concat(arr.slice(index + delCount));
+```
+
+```js
+const names = ['alpha', 'bravo', 'charlie'];
+const namesAndDelta = shank(names, 1, 0, 'delta'); // [ 'alpha', 'delta', 'bravo', 'charlie' ]
+const namesNoBravo = shank(names, 1, 1); // [ 'alpha', 'charlie' ]
+console.log(names); // ['alpha', 'bravo', 'charlie']
+```
+

tag_database

@@ -248,6 +248,7 @@ sdbm:math,utility,intermediate
 serializeCookie:utility,string,intermediate
 setStyle:browser,beginner
 shallowClone:object,beginner
+shank:array,intermediate
 show:browser,css,beginner
 shuffle:array,random,intermediate
 similarity:array,math,beginner

test/shank/shank.js

@@ -0,0 +1,5 @@
+const shank = (arr, index = 0, delCount = 0, ...elements) => 
+  arr.slice(0, index)
+     .concat(elements)
+     .concat(arr.slice(index + delCount));
+module.exports = shank;

test/shank/shank.test.js

@@ -0,0 +1,22 @@
+const expect = require("expect");
+const shank = require("./shank.js");
+
+test("shank is a Function", () => {
+  expect(shank).toBeInstanceOf(Function);
+});
+
+const names = ['alpha', 'bravo', 'charlie'];
+
+test("Returns an array with the added elements.", () => {
+  expect(shank(names, 1, 0, 'delta')).toEqual(['alpha', 'delta', 'bravo', 'charlie']);
+});
+
+test("Returns an array with the removed elements.", () => {
+  expect(shank(names, 1, 1)).toEqual(['alpha', 'charlie']);
+});
+
+test("Does not mutate the original array", () => {
+  shank(names, 1, 0, 'delta');
+  expect(names).toEqual(['alpha', 'bravo', 'charlie']);
+});
+