unadon

simple stack for undo/redo

Installaion

$ npm install unadon

Usage

var stack = require('unadon')();

stack.onStack = function(val) {
  console.log('stacked function which returns ' + val);
};

stack.onUndo = function(val) {
  console.log('undid function which returns ' + val);
};

stack.onRedo = function(val) {
  console.log('redid function which returns ' + val);
};

var i = 0;

// stack and execute
stack(function() {
  // redo function
  return ++i;
}, function() {
  // undo function
  return --i;
})

// undo
stack.undo();

// redo
stack.redo();

Here is a little bit more practical example, fetching the new value from remote, keeping it into closure for undo/redo.

function update(data) {
  var old = data.sheep;
  fetchSomethingFromRemote(function(newVal) {
    stack(function() {
      // set new value
      data.sheep = newVal;
    }, function() {
      // restore old value
      data.sheep = old;
    });
  });
}

update({ sheep: 'baaa' });

Methods

stack(redo, undo)

Register a pair of functions consists of function you would like to execute (which is the same as redo function) and it's opposite undo function.

stack.undo()

Put out and call the function at the top of the undo stack, then move it to the redo stack.

stack.redo()

Put out and call the function at the top of the redo stack, then move it to the undo stack.

stack.clear()

Clear all the stacked undo/redo functions. This function will be often called when something is saved.

stack.onStack

function called when a function is stacked (default: noop)

stack.onUndo

function called when undo function is called (default: noop)

stack.onRedo

function called when redo function is called (default: noop)

License

MIT