diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..30bc162
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/node_modules
\ No newline at end of file
diff --git a/data.js b/data.js
new file mode 100644
index 0000000..8a43e5d
--- /dev/null
+++ b/data.js
@@ -0,0 +1,32 @@
+module.exports = [
+  {
+    name: '자바스크립트 공부하기',
+    tags: ['programming', 'javascript'],
+    status: 'todo',
+    id: 12123123
+  },
+  {
+    name: '그림 그리기',
+    tags: ['picture', 'favorite'],
+    status: 'doing',
+    id: 35435345
+  },
+  {
+    name: '꽃구경하기',
+    tags: ['flower', 'favorite'],
+    status: 'done',
+    id: 7657
+  },
+  {
+    name: '저녁식사',
+    tags: ['dinner', 'food'],
+    status: 'todo',
+    id: 097989
+  },
+  {
+    name: '커피마시기',
+    tags: ['coffee', 'favorite'],
+    status: 'doing',
+    id: 65464
+  }
+];
diff --git a/design/pic1.jpg b/design/pic1.jpg
new file mode 100644
index 0000000..ee14737
Binary files /dev/null and b/design/pic1.jpg differ
diff --git a/design/pic2.jpg b/design/pic2.jpg
new file mode 100644
index 0000000..dd2796a
Binary files /dev/null and b/design/pic2.jpg differ
diff --git a/oop/app.js b/oop/app.js
new file mode 100644
index 0000000..69b5db5
--- /dev/null
+++ b/oop/app.js
@@ -0,0 +1,25 @@
+const readline = require('readline');
+const ValidCheck = module.require('./validCheck');
+const Todo = module.require('./todo.js');
+const todoList = module.require('./data.js');
+const Log = module.require('./log.js');
+
+const rl = readline.createInterface({
+	input: process.stdin,
+	output: process.stdout
+});
+rl.setPrompt('명령하세요 : ');
+
+rl.prompt();
+
+const myLog = new Log();
+const myTodo = new Todo(todoList, rl);
+
+rl.on('line', input => {
+	sendCommand(input);
+});
+
+const sendCommand = input => {
+	const myValidCheck = new ValidCheck(myTodo, myLog);
+	myValidCheck.parseCommand(input);
+};
diff --git a/oop/data.js b/oop/data.js
new file mode 100644
index 0000000..cf6697b
--- /dev/null
+++ b/oop/data.js
@@ -0,0 +1,32 @@
+module.exports = [
+	{
+		name: '자바스크립트 공부하기',
+		tags: ['programming', 'javascript'],
+		status: 'todo',
+		id: 12123123
+	},
+	{
+		name: '그림 그리기',
+		tags: ['picture', 'favorite'],
+		status: 'doing',
+		id: 312323
+	},
+	{
+		name: '고양이 모래 주문하기',
+		tags: ['cat', 'shopping'],
+		status: 'todo',
+		id: 78956
+	},
+	{
+		name: '밤코하기',
+		tags: ['study', 'favorite'],
+		status: 'done',
+		id: 46588
+	},
+	{
+		name: '워홀가기',
+		tags: ['travel', 'favorite'],
+		status: 'todo',
+		id: 19846
+	}
+];
diff --git a/oop/errorMessage.js b/oop/errorMessage.js
new file mode 100644
index 0000000..acc5c68
--- /dev/null
+++ b/oop/errorMessage.js
@@ -0,0 +1,7 @@
+module.exports = {
+	COMMAND_ERROR: '명령어가 올바르지 않습니다.',
+	ID_ERROR: 'ID가 존재하지 않습니다.',
+	STATUS_ERROR: '같은 상태로 변경할 수 없습니다.',
+	UNDO_ERROR: '더 이상 되돌릴 수 없습니다.',
+	REDO_ERROR: '더 이상 되돌리기를 취소할 수 없습니다.'
+};
diff --git a/oop/log.js b/oop/log.js
new file mode 100644
index 0000000..d52f142
--- /dev/null
+++ b/oop/log.js
@@ -0,0 +1,87 @@
+module.exports = Log = function(undoLimit = 3, defaultIndex = -1) {
+	(this.queue = []), (this.index = defaultIndex), (this.undoLimit = undoLimit);
+};
+
+Log.prototype.getIndex = function() {
+	return this.index;
+};
+
+Log.prototype.getLength = function() {
+	return this.queue.length;
+};
+
+Log.prototype.addLog = function(logDataObject) {
+	if (this.queue.length > this.undoLimit + 1) {
+		this.queue.shift();
+	}
+
+	while (this.queue.length > this.index + 1) {
+		this.queue.pop();
+	}
+
+	this.queue[++this.index] = {
+		action: logDataObject.action,
+		prevData: logDataObject.prevData,
+		nextData: logDataObject.nextData,
+		todoListIndex: logDataObject.todoListIndex
+	};
+};
+
+Log.prototype.undo = function() {
+	const action = this.queue[this.index].action;
+	const prevData = this.queue[this.index].prevData;
+	const nextData = this.queue[this.index].nextData;
+	const todoListIndex = this.queue[this.index].todoListIndex;
+	console.log(
+		`"${nextData.id}"번 항목 '${nextData.name}'이(가) ${nextData.status} 에서 ${prevData.status}로 변경되었습니다.`
+	);
+	this.index--;
+	if (action === 'add') {
+		return {
+			todoListIndex,
+			deleteCount: 1
+		};
+	} else if (action === 'delete') {
+		return {
+			todoListIndex,
+			deleteCount: 0,
+			data: prevData
+		};
+	} else if (action === 'update') {
+		return {
+			todoListIndex,
+			deleteCount: 1,
+			data: prevData
+		};
+	}
+};
+
+Log.prototype.redo = function() {
+	this.index++;
+	const action = this.queue[this.index].action;
+	const prevData = this.queue[this.index].prevData;
+	const nextData = this.queue[this.index].nextData;
+	const todoListIndex = this.queue[this.index].todoListIndex;
+
+	console.log(
+		`"${nextData.id}"번 항목 '${nextData.name}'이(가) ${prevData.status} 에서 ${nextData.status}로 변경되었습니다.`
+	);
+	if (action === 'add') {
+		return {
+			todoListIndex,
+			deleteCount: 0,
+			data: nextData
+		};
+	} else if (action === 'delete') {
+		return {
+			todoListIndex,
+			deleteCount: 1
+		};
+	} else if (action === 'update') {
+		return {
+			todoListIndex,
+			deleteCount: 1,
+			data: nextData
+		};
+	}
+};
diff --git a/oop/todo.js b/oop/todo.js
new file mode 100644
index 0000000..08002aa
--- /dev/null
+++ b/oop/todo.js
@@ -0,0 +1,122 @@
+require('date-utils');
+
+const commonDelaySecond = 1000;
+const updateDelaySecond = 3000;
+
+module.exports = Todo = function(todoList, readline) {
+	this.todoList = todoList;
+	this.readline = readline;
+};
+
+Todo.prototype.show = function(command) {
+	if (command === 'all') {
+		this.printAll();
+	} else {
+		this.printList(command);
+	}
+};
+
+Todo.prototype.getStatusList = function() {
+	const listOfStatus = this.todoList.reduce((acc, cur) => {
+		if (acc[cur.status] === undefined) {
+			acc[cur.status] = [cur.name];
+		} else {
+			acc[cur.status].push(cur.name);
+		}
+		return acc;
+	}, {});
+	return listOfStatus;
+};
+
+Todo.prototype.printAll = function() {
+	const listOfStatus = this.getStatusList();
+	let printResult = [];
+	for (let status in listOfStatus) {
+		printResult.push(`${status} : ${listOfStatus[status].length}개`);
+	}
+	console.log(`현재상태 : ${printResult.join(', ')}`);
+	this.readline.prompt();
+};
+
+Todo.prototype.printList = function(status) {
+	const listOfStatus = this.getStatusList();
+	const statusList = listOfStatus[status];
+	console.log(`${status}리스트 : 총 ${statusList.length} 건 : ${statusList.join(', ')}`);
+	this.readline.prompt();
+};
+
+Todo.prototype.add = function(name, tag) {
+	const id = this.getId();
+	const newData = {
+		name: name,
+		tag,
+		status: 'todo',
+		id: id
+	};
+	this.todoList.push(newData);
+	const prevData = Object.assign({}, newData);
+	prevData.status = '삭제';
+	console.log(`${newData.name} 1개가 추가되었습니다. (id : ${newData.id})`);
+
+	setTimeout(() => {
+		this.printAll();
+	}, commonDelaySecond);
+	return { action: 'add', prevData, nextData: newData, todoListIndex: this.todoList.length - 1 };
+};
+
+Todo.prototype.getId = function() {
+	const id = new Date();
+	return Number(id.toFormat('YYMMDDHH24MISS'));
+};
+
+Todo.prototype.checkValidId = function(id) {
+	let index;
+	const targetData = this.todoList.filter((element, innerIndex) => {
+		if (Number(id) === element.id) {
+			index = innerIndex;
+			return Number(id) === element.id;
+		}
+	});
+
+	if (targetData[0] === undefined) {
+		return false;
+	}
+	return index;
+};
+
+Todo.prototype.getStatus = function(index) {
+	return this.todoList[index].status;
+};
+
+Todo.prototype.delete = function(index) {
+	const deletingData = this.todoList[index];
+	console.log(`${deletingData.name}가 ${deletingData.status}에서 삭제됐습니다.`);
+	const nextData = Object.assign({}, this.todoList[index]);
+	nextData.status = '삭제';
+	this.todoList.splice(index, 1);
+	setTimeout(() => {
+		this.printAll();
+	}, commonDelaySecond);
+	return { action: 'delete', prevData: deletingData, nextData, todoListIndex: index };
+};
+
+Todo.prototype.update = function(index, status) {
+	const prevData = Object.assign({}, this.todoList[index]);
+	this.todoList[index].status = status;
+
+	setTimeout(() => {
+		console.log(`"${this.todoList[index].name}"가(이) ${status}로 변경되었습니다.`);
+		setTimeout(() => {
+			this.printAll();
+		}, commonDelaySecond);
+	}, updateDelaySecond);
+	return { action: 'update', prevData, nextData: this.todoList[index], todoListIndex: index };
+};
+
+Todo.prototype.undoAndRedo = function(obj) {
+	if (obj.data == undefined) {
+		this.todoList.splice(obj.todoListIndex, obj.deleteCount);
+	} else {
+		this.todoList.splice(obj.todoListIndex, obj.deleteCount, obj.data);
+	}
+};
diff --git a/oop/validCheck.js b/oop/validCheck.js
new file mode 100644
index 0000000..1d5217b
--- /dev/null
+++ b/oop/validCheck.js
@@ -0,0 +1,107 @@
+const errorMessage = module.require('./errorMessage.js');
+
+module.exports = class ValidCheck {
+	constructor(todo, log) {
+		(this.todo = todo), (this.log = log);
+	}
+	parseCommand(input) {
+		try {
+			const inputArray = input.split('$');
+			const action = inputArray.splice(0, 1)[0];
+			const condition = inputArray;
+			const regExp = /^show$|^add$|^delete$|^update$|^undo$|^redo$/;
+			const matchRegExp = action.match(regExp);
+
+			if (matchRegExp === null) {
+				throw new Error('COMMAND_ERROR');
+			} else {
+				this[`${action}Check`](...condition);
+			}
+		} catch (error) {
+			console.log(errorMessage[error.message]);
+			this.todo.readline.prompt();
+		}
+	}
+
+	excuteTodo(action, ...condition) {
+		if (action === 'show') {
+			this.todo[action](...condition);
+			return;
+		}
+		this.log.addLog(this.todo[action](...condition));
+	}
+
+	excuteLog(action) {
+		this.todo.undoAndRedo(this.log[action]());
+		this.todo.readline.prompt();
+	}
+
+	showCheck(element) {
+		const regExp = /^all$|^todo$|^doing$|^done$/;
+		const command = element.match(regExp);
+		if (command === null) {
+			throw new Error('COMMAND_ERROR');
+		}
+		this.excuteTodo('show', command[0]);
+	}
+
+	addCheck(name, tag) {
+		if (name === undefined || tag === undefined || name === '' || tag === '') {
+			throw new Error('COMMAND_ERROR');
+		}
+		const tagResult = tag.replace(/\[|\'|\"|\]/g, '').split(',');
+
+		this.excuteTodo('add', name, tagResult);
+	}
+
+	deleteCheck(id) {
+		const validIndex = this.todo.checkValidId(id);
+
+		if (validIndex === false) {
+			throw new Error('ID_ERROR');
+		}
+
+		this.excuteTodo('delete', validIndex);
+	}
+
+	updateCheck(id, status) {
+		if (status === undefined) {
+			throw new Error('COMMAND_ERROR');
+		}
+
+		const validIndex = this.todo.checkValidId(id);
+		if (validIndex === false) {
+			throw new Error('ID_ERROR');
+		}
+
+		const regExp = /^todo$|^doing$|^done$/;
+		const matchRegExp = status.match(regExp);
+
+		if (matchRegExp === null) {
+			throw new Error('COMMAND_ERROR');
+		} else if (this.todo.getStatus(validIndex) === status) {
+			throw new Error('STATUS_ERROR');
+		}
+
+		this.excuteTodo('update', validIndex, status);
+	}
+
+	undoCheck() {
+		const index = this.log.getIndex();
+		if (index < 0) {
+			throw new Error('UNDO_ERROR');
+		}
+
+		this.excuteLog('undo');
+	}
+
+	redoCheck() {
+		const index = this.log.getIndex();
+		const length = this.log.getLength();
+		if (index >= length - 1) {
+			throw new Error('REDO_ERROR');
+		}
+
+		this.excuteLog('redo');
+	}
+};
diff --git a/todos.js b/todos.js
new file mode 100644
index 0000000..47e02aa
--- /dev/null
+++ b/todos.js
@@ -0,0 +1,54 @@
+const todos = require('./data');
+
+class Todo {
+	constructor(todos) {
+		this.todos = todos;
+		this.todoCount = this.setTodoCount(todos);
+	}
+
+	setTodoCount(todos) {
+		return todos.reduce((acc, cur) => {
+			acc[cur.status] = acc[cur.status] === undefined ? [cur.name] : acc[cur.status].concat(cur.name);
+			return acc;
+		}, {});
+	}
+
+	show(type, condition) {
+		let result;
+		if (type === 'status') {
+			if (condition === 'all') {
+				result = this.printAll();
+			} else {
+				result = this.printStatus(condition);
+			}
+		} else {
+			result = this.printTags(condition);
+		}
+		console.log(result);
+	}
+
+	printAll() {
+		return Object.entries(this.todoCount).reduce((acc, cur) => {
+			return (acc += `${cur[0]}: ${cur[1].length}개 `);
+		}, '현재상태 : ');
+	}
+
+	printStatus(status) {
+		return `${status}리스트 총 ${this.todoCount[status].length}건 : ${this.todoCount[status].join(', ')}`;
+	}
+
+	printTags(tag) {
+		const tagArr = this.todos.filter(todo => todo.tags.includes(tag)).map(obj => obj.name);
+		return `${tag} 키워드 검색 결과 : ${tagArr.join(', ')}`;
+	}
+}
+
+const todo = new Todo(todos);
+
+todo.show('status', 'all');
+todo.show('status', 'todo');
+todo.show('status', 'doing');
+todo.show('status', 'done');
+todo.show('tag', 'favorite');
+todo.show('tag', 'food');
+todo.show('tag', 'javascript');