Travis build: 1734

README.md

@@ -344,6 +344,7 @@ average(1, 2, 3);
 * [`matches`](#matches)
 * [`matchesWith`](#matcheswith)
 * [`merge`](#merge)
+* [`nest`](#nest)
 * [`objectFromPairs`](#objectfrompairs)
 * [`objectToPairs`](#objecttopairs)
 * [`omit`](#omit)
@@ -6259,6 +6260,46 @@ merge(object, other); // { a: [ { x: 2 }, { y: 4 }, { z: 3 } ], b: [ 1, 2, 3 ],
 <br>[⬆ Back to top](#table-of-contents)
 
 
+### nest
+
+Given a flat array of objects linked to one another, it will nest them recursively.
+Useful for nesting comments, such as the ones on reddit.com.
+
+Use recursion. Use `Array.filter()` to filter the items where the `id` matches the `link`,
+then use `Array.map()` to map each one to a new object that has a `children` property which
+recursively nests the items based on which ones are children of the current item. Omit the second 
+argument, `id`, to default to `null` which indicates the object is not linked to another one (i.e.,
+it is a top level). Omit the third argument, `link`, to use `'parent_id'` as the default property
+which links the object to another one by its `id`.
+
+```js
+const nest = (items, id = null, link = 'parent_id') =>
+  items
+    .filter(item => item[link] === id)
+    .map(item => ({ ...item, children: nest(items, item.id) }));
+```
+
+<details>
+<summary>Examples</summary>
+
+```js
+// One top level comment
+const comments = [
+  { id: 1, parent_id: null },
+  { id: 2, parent_id: 1 },
+  { id: 3, parent_id: 1 },
+  { id: 4, parent_id: 2 },
+  { id: 5, parent_id: 4 }
+];
+const nestedComments = nest(comments); // [{ id: 1, parent_id: null, children: [...] }]
+```
+
+
+</details>
+
+<br>[⬆ Back to top](#table-of-contents)
+
+
 ### objectFromPairs
 
 Creates an object from the given key-value pairs.

snippets/nest.md

@@ -12,7 +12,9 @@ which links the object to another one by its `id`.
 
 ```js
 const nest = (items, id = null, link = 'parent_id') =>
-  items.filter(item => item[link] === id).map(item => ({ ...item, children: nest(items, item.id) }))
+  items
+    .filter(item => item[link] === id)
+    .map(item => ({ ...item, children: nest(items, item.id) }));
 ```
 
 ```js
@@ -23,7 +25,7 @@ const comments = [
   { id: 3, parent_id: 1 },
   { id: 4, parent_id: 2 },
   { id: 5, parent_id: 4 }
-]
-const nestedComments = nest(comments) // [{ id: 1, parent_id: null, children: [...] }]
+];
+const nestedComments = nest(comments); // [{ id: 1, parent_id: null, children: [...] }]
 ```