Add find method

README.md

@@ -55,13 +55,13 @@ Default export, the class that holds and manages a list.
 Call it with either a forEach-able (like an array) or a set of
 arguments, to initialize the list.
 
-The Array-ish methods all act like you'd expect.  No magic length,
+The Array-ish methods all act like you'd expect. No magic length,
 though, so if you change that it won't automatically prune or add
 empty spots.
 
 ### Yallist.create(..)
 
-Alias for Yallist function.  Some people like factories.
+Alias for Yallist function. Some people like factories.
 
 #### yallist.head
 
@@ -73,7 +73,7 @@ The last node in the list
 
 #### yallist.length
 
-The number of nodes in the list.  (Change this at your peril.  It is
+The number of nodes in the list. (Change this at your peril. It is
 not magic like Array length.)
 
 #### yallist.toArray()
@@ -90,7 +90,7 @@ Call a function on each item in the list, in reverse order.
 
 #### yallist.get(n)
 
-Get the data at position `n` in the list.  If you use this a lot,
+Get the data at position `n` in the list. If you use this a lot,
 probably better off just using an Array.
 
 #### yallist.getReverse(n)
@@ -156,15 +156,15 @@ Insert one or more items to the head of the list.
 
 #### yallist.unshiftNode(node)
 
-Move a Node object to the front of the list.  (That is, pull it out of
+Move a Node object to the front of the list. (That is, pull it out of
 wherever it lives, and make it the new head.)
 
 If the node belongs to a different list, then that list will remove it
 first.
 
 #### yallist.pushNode(node)
 
-Move a Node object to the end of the list.  (That is, pull it out of
+Move a Node object to the end of the list. (That is, pull it out of
 wherever it lives, and make it the new tail.)
 
 If the node belongs to a list already, then that list will remove it
@@ -178,14 +178,18 @@ and tail and other nodes.
 Will throw an error if you try to have a list remove a node that
 doesn't belong to it.
 
+#### yallist.find(predicate)
+
+Like Array.find.
+
 ### Yallist.Node
 
 The class that holds the data and is actually the list.
 
 Call with `const n = new Node(value, previousNode, nextNode)`
 
 Note that if you do direct operations on Nodes themselves, it's very
-easy to get into weird states where the list is broken.  Be careful :)
+easy to get into weird states where the list is broken. Be careful :)
 
 #### node.next
 
@@ -201,5 +205,5 @@ The data the node contains.
 
 #### node.list
 
-The list to which this node belongs.  (Null if it does not belong to
+The list to which this node belongs. (Null if it does not belong to
 any list.)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "yallist",
-  "version": "5.0.0",
+  "version": "5.1.0",
   "description": "Yet Another Linked List",
   "files": [
     "dist"

src/index.ts

@@ -397,6 +397,22 @@ export class Yallist<T = unknown> {
     this.tail = head
     return this
   }
+
+  find(predicate: (value: T, index: number) => boolean) {
+    let walker = this.head
+    let index = 0
+
+    while (walker !== undefined) {
+      if (predicate(walker.value, index)) {
+        return walker
+      }
+
+      walker = walker.next
+      index++
+    }
+
+    return undefined
+  }
 }
 
 // insertAfter undefined means "make the node the new head of list"

test/basic.js

@@ -303,3 +303,15 @@ t.test('splice bug', t => {
   t.same(myList.toArray(), [1, 'should be second item', 2, 3])
   t.end()
 })
+
+t.test('find', t => {
+  const ll = new Yallist([1, 2, 3, 4, 5])
+
+  const foundNode = ll.find(value => value === 3)
+  t.equal(foundNode?.value, 3)
+
+  const notFoundNode = ll.find(value => value === 6)
+  t.equal(notFoundNode, undefined)
+
+  t.end()
+})