卡在 else if 循环中

Question

我正在为一个班级做一个练习，我们正在创建一个 Todo 列表。

我的问题是，当我输入 Todo 并按 Enter 键时，我收到消息Enter new Todo ，而不是Added todo 。

看来我被困在这个else if循环中，它不会转到下一个 else if语句。

 var todos = ["Buy New Turtle"]; window.setTimeout(function() { var input = prompt("What would you like to do?"); while(input !== "quit") { if(input === "list") { console.log("**********"); todos.forEach(function(todo, i) { console.log(i + ": " + todo); }) console.log("**********") } else if(input === "new") { var newTodo = prompt("Enter new todo"); todos.push(newTodo); console.log("Added todo"); } else if(input === "delete"){ var index = prompt("Enter index of todo to delete"); todos.splice(index, 1); } } input = prompt("What would you like to do?"); console.log("OK, YOU QUIT THE APP"); }, 500);

Answer 1

您需要将input的重新声明放在while循环中。 还要检查input是否为真 - 这样，如果有人关闭提示框，它就不会崩溃。

 var todos = ["Buy New Turtle"]; window.setTimeout(function() { var input = prompt("What would you like to do?"); while (input !== "quit" && input) { if (input === "list") { console.log("**********"); todos.forEach(function(todo, i) { console.log(i + ": " + todo); }) console.log("**********") } else if (input === "new") { var newTodo = prompt("Enter new todo"); todos.push(newTodo); console.log("Added todo"); } else if (input === "delete") { var index = prompt("Enter index of todo to delete"); todos.splice(index, 1); } input = prompt("What would you like to do?"); } console.log("OK, YOU QUIT THE APP"); }, 500);

Answer 2

您的线路：

input = prompt("What would you like to do?"); 位于while循环之外，因此每次输入待办事项时， input变量的值始终为“new”。

查看附加的片段以进行更正：

 var todos = ["Buy New Turtle"]; window.setTimeout(function() { var input = prompt("What would you like to do?"); while(input !== "quit") { if(input === "list") { console.log("**********"); todos.forEach(function(todo, i) { console.log(i + ": " + todo); }) console.log("**********") } else if(input === "new") { var newTodo = prompt("Enter new todo"); todos.push(newTodo); console.log("Added todo"); } else if(input === "delete"){ var index = prompt("Enter index of todo to delete"); todos.splice(index, 1); } // this line was moved into the while loop input = prompt("What would you like to do?"); } console.log("OK, YOU QUIT THE APP"); }, 500);

Answer 3

var todos = ["Buy New Turtle"];
newTodo = [];

window.setTimeout(function() {

  var input = prompt("What would you like to do?");

  while(input !== "quit") {

    if(input === "list") {
      console.log("**********");
      todos.forEach(function(todo, i) {
        console.log(i + ": " + todo);
      })
      console.log("**********")
    }
    else if(input === "new") {
      var newTodo = prompt("Enter new todo");
      todos.push(newTodo);
      console.log("Added todo");
      }

    else if(input === "delete"){
      var index = prompt("Enter index of todo to delete");
      todos.splice(index, 1);
      }
    input = prompt("What would you like to do?");
  }


  console.log("OK, YOU QUIT THE APP");
}, 500);`enter code here`