0.2.2 • Published 5 years ago
fast-undo v0.2.2
fast-undo
Efficient data structure for handling undo states.
// create an empty undo history
const history = undo.history()
// insert a few values
history.insert('cat')
history.insert('dog')
history.insert('rabbit')
// undo
history.undo() // cat <| dog |> rabbit
// redo
history.redo() // dog <| rabbit |> EMPTY
// export
history.toJSON() // '{"past":["dog","cat"],"present":"rabbit","future":[]}'
Install as an NPM module:
$ npm install fast-undo
Works as a higher-order reducer with Redux, or similiar:
import { combineReducers } from 'redux';
import { withHistory } from 'fast-undo';
combineReducers({
undoableReducer: withHistory(myReducer)
});
See the tests.js file for some more inspiration.
API
init
function init<T>(a: T): History<T>;
undo
function undo<T>(a: History<T>): History<T>;
redo
function redo<T>(a: History<T>): History<T>;
insert
function insert<T>(a: History<T>, b: T): History<T>;
prune
function prune<T>(history: History<T>, size?: number): History<T>;
serialize
function serialize<T>(a: History<T>): JSONHistory<T>;
deserialize
function deserialize<T>(a: JSONHistory<T>): History<T>;
history
function history<T>(a: T): {
undo: () => History<T>;
redo: () => History<T>;
insert: (a: T) => History<T>;
get: () => History<T>;
toJSON: () => string;
};
withHistory
function withHistory<T>(a: Reducer<T>): Reducer<History<T>>;