use-list-state

Manage array state
Import

Usage

use-list-state hook provides an API to work with list state:

const [values, handlers] = useListState([{ a: 1 }]);
// add one or more items to the end of the list
const append = () => handlers.append({ a: 2 });
// values -> [{ a: 1 }, { a: 2 }]
// add one or more items to the start of the list
const prepend = () => handlers.prepend({ a: 3 }, { a: 4 });
// values -> [{ a: 3 }, { a: 4 }, { a: 1 }, { a: 2 }]
// remove items at given positions
const remove = () => handlers.remove(0, 2);
// values -> [{ a: 4 }, { a: 2 }]
// insert one or more items at given position
const insert = () => handlers.insert(1, { a: 5 });
// values -> [{ a: 4 }, { a: 5 }, { a: 2 }]
// apply function to each element of the list
const apply = () => handlers.apply((item, index) => ({ a: item.a * index }));
// values -> [{ a: 0 }, { a: 5 }, { a: 4 }]
// move item from one position to another
const reorder = () => handlers.reorder({ from: 2, to: 0 });
// values -> [{ a: 4 }, { a: 0 }, { a: 5 }]
// apply function to each element that matches condition
const applyWhere = () =>
handlers.applyWhere(
(item) => item.a > 0,
(item) => ({ a: item.a + 2 })
);
// values -> [{ a: 6 }, { a: 0 }, { a: 7 }]
// set entirely new state
const setState = () => handlers.setState([{ a: 6 }, { a: 7 }]);
// values -> [{ a: 6 }, { a: 7 }]
// set individual item at given position
const setItem = () => handlers.setItem(0, { a: 8 });
// values -> [{ a: 8 }, { a: 7 }]
// set item property at given position
const setItemProp = () => handlers.setItemProp(1, 'a', 'new-prop');
// values -> [{ a: 8 }, { a: 'new-prop' }]

API

use-list-state takes array as single argument and returns list values and handlers to change them in tuple, similar to react's useState hook.

Hook provides handlers to work with array data:

  • append – add items to the end of the list
  • prepend – add items to the start of the list
  • pop – remove last item
  • shift – remove first item
  • insert – insert items at given index
  • remove – remove items at given indices
  • reorder – move item from one position to another
  • apply – apply given function to all items in the list
  • applyWhere - apply given function to selective items using condition
  • setItem – replace item at given index
  • setItemProp – set item property at given index
  • setState – set list state with react action

Indeterminate state checkbox example

TypeScript

Definition

function useListState<T>(initialValue: T[] = []): [
T[],
{
setState: Dispatch<SetStateAction<T[]>>;
append: (...items: T[]) => void;
prepend: (...items: T[]) => void;
insert: (index: number, ...items: T[]) => void;
apply: (fn: (item: T, index?: number) => T) => void;
pop: () => void;
shift: () => void;
applyWhere: (
condition: (item: T, index?: number) => boolean,
fn: (item: T, index?: number) => T)
) => void;
remove: (...indices: number[]) => void;
reorder: ({ from, to }: { from: number; to: number }) => void;
setItem: (index: number, item: T) => void;
setItemProp: <K extends keyof T, U extends T[K]>(index: number, prop: K, value: U) => void;
}
];

Set item type

By default, use-list-state will use type from initialValues. If you init hook with empty array, you must specify item type:

useListState(['hello']); // ok, item type is string
useListState([]); // not ok, item type is any
useListState<string>([]); // ok, item type is string