Practical JavaScript by Gordan Zhu Todo app.

app.js

//created an object TodosList
var TodosList = {
    todos: [],//todos array
    displayTodos:function() {//method that displays values in array
     console.log('My Todos:');
     if(this.todos.length===0){//check if it's empty
      console.log('Your array is empty.');
     }else {//if it's not empty
    for(i=0;i<this.todos.length;i++){
     //console.log(this.todos[i].todoText);
     if(this.todos[i].completed===true){//check if its completed
      console.log('( )',this.todos[i].todoText);
     }else{
      console.log('(x)',this.todos[i].todoText);
     }
    }
     }
  },
      addTodo: function(todoText) {
      this.todos.push({
      todoText: todoText, 
      completed: false
    });
      this.displayTodos();
  },
    changeTodo: function(position,todoText){
    this.todos[position].todoText= todoText;
    this.displayTodos();
  },
    deleteTodo: function(position){
    this.todos[position];
    this.displayTodos();
  },
  toggleCompleted:function(position){
   var todo = this.todos[position];
  todo.completed = !todo.completed;
   this.displayTodos();
  }
};