# dll
> a lightweight, fast & flexible doubly linked list
Latest version **0.2.0** (published 2014-09-29) · Apache 2.0 license · 0 weekly downloads
## Install
```sh
npm install dll
pnpm add dll
yarn add dll
bun add dll
```
## Health
**Score 15/100 (F)** — status: abandoned.
Positive: no vulnerabilities.
Warnings: low downloads; no types; no esm support; pre 1.0.
Negative: abandoned; low maintenance score.
## Facts
| | |
|---|---|
| Version | 0.2.0 |
| Published | 2014-09-29 |
| First published | 2014-09-22 |
| Weekly downloads | 0 |
| License | Apache 2.0 |
| TypeScript types | none |
| Module format | CommonJS |
| Dependencies | 0 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 1 |
| Author | Louis Acresti |
| Maintainers | namuol |
| Keywords | doubly, linked, list |
## Links
- npm: https://www.npmjs.com/package/dll
- Repository: https://github.com/namuol/dll
- Issues: https://github.com/namuol/dll/issues
- npm.io page: https://npm.io/package/dll
## Recent versions
- 0.2.0 (latest) — 2014-09-29
- 0.1.0 — 2014-09-22
- 0.0.0 — 2014-09-22
## README
# dll [](https://drone.io/github.com/namuol/dll/latest) [](https://david-dm.org/namuol/dll#info=devDependencies)
A lightweight, fast & flexible doubly linked list for JavaScript.
```js
var currentID = 0;
function Food (name) {
this.name = name;
// a unique id field is required:
this._id = currentID;
currentID += 1;
}
var entityA = new Food('Bacon'),
entityB = new Food('Brocolli'),
entityC = new Food('Sausage'),
entityD = new Food('Steak');
var LinkedList = require('dll');
var list = new LinkedList();
list.add(entityA);
list.add(entityB);
list.add(entityC);
list.add(entityD);
console.log(list.length); // "4"
// Iterating is easy:
var itr = list.first;
while (itr) {
console.log(itr.obj.name);
itr = itr.next;
}
// Output:
// Bacon
// Brocolli
// Sausage
// Steak
// Or even easier:
list.each(function (obj) {
console.log (itr.obj.name);
});
assert( list.contains(entityC) === true );
list.remove(entityC);
assert( list.contains(entityC) === false );
// Iterating backwards is easy:
itr = list.last;
while (itr) {
console.log(itr.obj.name);
itr = itr.prev;
}
// Output:
// Steak
// Sausage
// Bacon
list.clear();
console.log(list.length); // "0"
```
### Caveats
- Only objects are supported. No primitives.
- Objects must have a unique ID property (default is `_id`, but it can be changed with [`dll.config.idPropertyName`](#api-config-idPropertyName)).
- Duplicate items are not supported.
### API
```js
var LinkedList = require('dll');
```
#### LinkedList.config.idPropertyName
*Type:* **String** *Default: `"_id"`*
The name of the property used to uniquely identify objects.
You are required to have a unique ID property on any objects that
are added to a linked list, but you can call it whatever you want by
changing the string value of this property.
#### new LinkedList()
Create a new linked list.
#### list.first
*Type:* [**Node**](#api-node)
The first node in the list.
If the list is empty, `list.first` will be `null`.
#### list.last
*Type:* [**Node**](#api-node)
The last node in the list.
If the list is empty, `list.last` will be `null`.
#### list.length
The number of objects in the list.
#### list.add(obj)
Add an object to a list. If a list already contains the object,
this will have no effect on the list.
**Always returns `obj`**
#### list.remove(obj)
Remove an object from the list.
**Returns `obj` if the object was removed, `false` if it was not part of the list**
#### list.clear(obj)
Removes all objects from the list and sets its length to zero.
#### list.each(function (obj) {/* ... */})
Call a function for every object in the list.
#### Node
A container representing a location within the list.
#### Node.obj
*Type:* **Object**
The object that is at this location in the list.
#### Node.next
*Type:* [**Node**](#api-node)
The node that follows this node.
If this is the last node in the list, `next` will be `null`.
#### Node.prev
*Type:* [**Node**](#api-node)
The node that precedes this node.
If this is the first node in the list, `prev` will be `null`.
## License
Apache 2.0
## Install
```bash
npm install dll --save
```
----
[](https://github.com/igrigorik/ga-beacon)
---
_Source: https://npm.io/package/dll · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._