InputStack.js

// InputStack.js - InputStack...
// see: https://github.com/jzaefferer/undo
//

"use strict";

function InputStack() {
	this.init();
}

InputStack.prototype = {
	init: function () {
		this.aInput = [];
		this.iStackPosition = -1;
		return this;
	},
	getInput: function () {
		return this.aInput[this.iStackPosition];
	},
	clearRedo: function () {
		this.aInput = this.aInput.slice(0, this.iStackPosition + 1);
		return this;
	},
	save: function (sInput) {
		this.clearRedo();
		this.aInput.push(sInput);
		this.iStackPosition += 1;
		return this;
	},
	canUndo: function () {
		return this.iStackPosition >= 0;
	},
	canUndoKeepOne: function () {
		return this.iStackPosition > 0;
	},
	undo: function () {
		this.iStackPosition -= 1;
		return this.getInput();
	},
	canRedo: function () {
		return this.iStackPosition < this.aInput.length - 1;
	},
	redo: function () {
		this.iStackPosition += 1;
		return this.getInput();
	}
};


if (typeof module !== "undefined" && module.exports) {
	module.exports = InputStack;
}
// end