neft

# List > **API Reference** ▸ **List**  Access it with: ```javascript const { List } = Neft; ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee) * * * ### `constructor()` <dl><dt>Parameters</dt><dd><ul><li>data — Array — optional</li></ul></dd></dl> Creates a new list instance. ```javascript var list = new List([1, 2]); list instanceof List; // true ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#listconstructorarray-data) * * * ### `onChange()` <dl><dt>Parameters</dt><dd><ul><li>oldValue — Any</li><li>index — Integer</li></ul></dd><dt>Type</dt><dd>Signal</dd></dl> Signal called on each value change. > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#signal-listonchangeany-oldvalue-integer-index) * * * ### `onInsert()` <dl><dt>Parameters</dt><dd><ul><li>value — Any</li><li>index — Integer</li></ul></dd><dt>Type</dt><dd>Signal</dd></dl> Signal called when a value was added. > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#signal-listoninsertany-value-integer-index) * * * ### `onPop()` <dl><dt>Parameters</dt><dd><ul><li>oldValue — Any</li><li>index — Integer</li></ul></dd><dt>Type</dt><dd>Signal</dd></dl> Signal called when a value was removed. > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#signal-listonpopany-oldvalue-integer-index) * * * ### `length` <dl><dt>Type</dt><dd>Integer</dd><dt>Read Only</dt></dl> Amount of values stored in the list. ```javascript var list = new List(['a', 'b']); list.length; // 2 ``` * * * ### `set()` <dl><dt>Parameters</dt><dd><ul><li>index — Integer</li><li>value — Any</li></ul></dd><dt>Returns</dt><dd>Any</dd></dl> Sets the given value under the given index. The index must exists in the list. The value can't be an `undefined`. Use `pop()` instead. Calls `onChange()` signal. ```javascript var types = new List(['fantasy', 'Thriller']); types.onChange.connect(function(oldVal, i){ console.log("element "+oldVal+" changed to "+this[i]); }); types.set(0, 'Fantasy'); // element fantasy changed to Fantasy types.set(0, 'Fantasy'); // nothing changed ... ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#any-listsetinteger-index-any-value) * * * ### `append()` <dl><dt>Parameters</dt><dd><ul><li>value — Any</li></ul></dd><dt>Returns</dt><dd>Any</dd></dl> Adds the given value on the end on the list. The value can't be an `undefined`. Calls `onInsert()` signal. ```javascript var fridge = new List(['apple', 'milk']); fridge.onInsert.connect(function(val, i){ console.log(val+" appended!"); }); fridge.append('cheese'); // cheese appended! console.log(fridge.items()); // apple, milk, cheese ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#any-listappendany-value) * * * ### `insert()` <dl><dt>Parameters</dt><dd><ul><li>index — Integer</li><li>value — Any</li></ul></dd><dt>Returns</dt><dd>Any</dd></dl> Add the given value under the given index. The index can't be greater than the list length. The value can't be an `undefined`. Calls `onInsert()` signal. ```javascript var list = new List(['a', 'b']); list.onInsert.connect(function(val, i){ console.log("new element "+val+" inserted at index "+i); }); list.insert(1, 'c'); // new element c inserted at index 1 console.log(list.items()); // ['a', 'c', 'b'] ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#any-listinsertinteger-index-any-value) * * * ### `extend()` <dl><dt>Parameters</dt><dd><ul><li>items — Object</li></ul></dd><dt>Returns</dt><dd>List</dd></dl> Appends all values stored in the given items into the list. Calls `onInsert()` signal for each value. > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#list-listextendobject-items) * * * ### `remove()` <dl><dt>Parameters</dt><dd><ul><li>value — Any</li></ul></dd><dt>Returns</dt><dd>Any</dd></dl> Removes the given value from the list. Calls `onPop()` signal. ```javascript var list = new List(['a', 'b']); list[1]; // b list.remove('b'); list[1]; // undefined list; // ['a'] ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#any-listremoveany-value) * * * ### `pop()` <dl><dt>Parameters</dt><dd><ul><li>index — Integer — optional</li></ul></dd><dt>Returns</dt><dd>Any</dd></dl> Removes the value stored in the list under the given index. The index must exists in the list. Calls `onPop()` signal. ```javascript var list = new List(['a', 'b']); list[1]; // b list.pop(1); list[1]; // undefined list; // ['a'] ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#any-listpopinteger-index) * * * ### `clear()` Removes all values stored in the list. Calls `onPop()` signal for each value. ```javascript var list = new List(['a', 'b']); list.onPop.connect(function(oldVal, i){ console.log("Element "+oldVal+" popped!"); }); console.log(list.items()); // ['a', 'b'] list.clear() // Element b popped! // Element a popped! console.log(list); // [] ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#listclear) * * * ### `index()` <dl><dt>Parameters</dt><dd><ul><li>value — Any</li></ul></dd><dt>Returns</dt><dd>Integer</dd></dl> Returns the given value index in the list. Returns `-1` if the value doesn't exist in the list. ```javascript var list = new List(['a', 'b']); list.index('b'); // 1 list.index('c'); // -1 ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#integer-listindexany-value) * * * ### `has()` <dl><dt>Parameters</dt><dd><ul><li>value — Any</li></ul></dd><dt>Returns</dt><dd>Boolean</dd></dl> Returns `true` if the given value exists in the list. ```javascript var list = new List(['a', 'b']); list.has('a'); // true list.has('ab123'); // false ``` > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#boolean-listhasany-value) * * * ### `toArray()` <dl><dt>Returns</dt><dd>Array</dd></dl> > [`Source`](https://github.com/Neft-io/neft/blob/f9c128ccb37aa79380c961e878cd76ec9e79c99e/src/list/index.litcoffee#array-listtoarray)