console.log 中没有 output。初学者问题

Question

I'm reading Head 1st JavaScript book and try to learn the language as much as i can.我正在阅读 Head 1st JavaScript 这本书，并尽可能多地学习这门语言。 Wanted to to all the problems from the book.想解决书中的所有问题。 After i did so for one of the problems, and wrote the code as i thought, and checked the solution, i changed it to reflect the solution in the book even thou it worked for me.在我针对其中一个问题这样做后，按照我的想法编写了代码，并检查了解决方案，我对其进行了更改以反映书中的解决方案，即使它对我有用。 The thing is, when i want to "print" in the console now, nothing shows up and idk why... i don't see nor have a problem... Any idea why the console.log will not output anything?问题是，当我现在想在控制台中“打印”时，什么也没有显示，我知道为什么……我没有看到也没有问题……知道为什么 console.log 不会 output 任何东西吗？ Thanks!谢谢！

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        function Coffee(roast, ounces) {
            this.roast = roast;
            this.ounces = ounces;
            this.getSize = function() {
            if (this.ounces === 8) {
                return "small";
            } else if (this.ounces === 12) {
                return "medium";
            } else (this.ounces === 16); {
                return "large";
            }
        };
            this.toString = function() {
                return "You have ordered a " + this.getSize() + " " + this.roast + " coffee.";
            };
        }
        var csmall = new Coffee ("House Blend",  "8");
        var cmedium = new Coffee ("House Blend", "12");
        var clarge = new Coffee ("Dark Roast", "16");
        var coffees = [csmall, cmedium, clarge];

        for (var i = 0; i < coffees.length; i++) {
            coffees[i].toString();
        }
    </script>
</head>
<body>
    
</body>
</html>

This is the way i wrote the code and worked.这就是我编写代码和工作的方式。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        function Coffee(roast, size, ounces) {
            this.roast = roast;
            this.size = size;
            this.ounces = ounces;
            this.getSize = function() {
            if (this.ounces === 8) {
                console.log("You have ordered a " + this.size + " " + this.roast + " coffee.");
            } else if (this.ounces === 12) {
                console.log("You have ordered a " + this.size + " " + this.roast + " coffee.");
            } else (this.ounces === 16); {
                console.log("You have ordered a " + this.size + " " + this.roast + " coffee.");
            }
            };
        }
        var csmall = new Coffee ("House Blend", "small",  "8");
        var cmedium = new Coffee ("House Blend", "medium", "12");
        var clarge = new Coffee ("Dark Roast", "large", "16");
        var coffees = [csmall, cmedium, clarge];

        for (var i = 0; i < coffees.length; i++) {
            coffees[i].getSize();
        }
    </script>
</head>
<body>
    
</body>
</html>

Answer 1

In above code console log has not been used so this is why you haven't seen any thing in the console在上面的代码中，控制台日志没有被使用，所以这就是为什么你没有在控制台中看到任何东西的原因

for (var i = 0; i < coffees.length; i++) {
        coffees[i].toString();
        console.log(String(coffees[i])); // <-- add here
    }

Still it would give incorrect result becuase it used === in the function which means the type of the value supplied will also match with type in the function它仍然会给出不正确的结果，因为它在 function 中使用了 === 这意味着提供的值的类型也将与 function 中的类型匹配

It used integers in function but supplied value in string see the code below它在 function 中使用了整数，但在字符串中提供了值，请参见下面的代码

if (this.ounces === 8) { // used === to match type as well here it is integer
            return "small";
        } else if (this.ounces === 12) {
            return "medium";
        } else (this.ounces === 16); {
            return "large";
        }
    };
        this.toString = function() {
            return "You have ordered a " + this.getSize() + " " + this.roast + " coffee.";
        };
    }
    var csmall = new Coffee ("House Blend",  "8"); // passing it as string "8" it should be just 8
    var cmedium = new Coffee ("House Blend", "12");
    var clarge = new Coffee ("Dark Roast", "16");

Correct Code should be like this正确的代码应该是这样的

<script>
    function Coffee(roast, ounces) {
        this.roast = roast;
        this.ounces = ounces;
        this.getSize = function() {
        if (this.ounces === 8) {
            return "small";
        } else if (this.ounces === 12) {
            return "medium";
        } else (this.ounces === 16); {
            return "large";
        }
    };
        this.toString = function() {
            return "You have ordered a " + this.getSize() + " " + this.roast + " coffee.";
        };
    }
    var csmall = new Coffee ("House Blend",  8);
    var cmedium = new Coffee ("House Blend", 12);
    var clarge = new Coffee ("Dark Roast", 16);
    var coffees = [csmall, cmedium, clarge];

    for (var i = 0; i < coffees.length; i++) {
        coffees[i].toString();
        console.log(String(coffees[i]));
    }
</script>

But in the secon code which is done by you...但是在你完成的第二个代码中......

I beleive the real problem was to use logic and convert ounces into size by getsize function where as you directly used sizes in your solution我相信真正的问题是使用逻辑并通过 getsize function 将盎司转换为尺寸，因为您在解决方案中直接使用了尺寸

console.log 中没有 output。初学者问题

问题描述

1 个解决方案

解决方案1
0 2022-12-03 09:07:52

console.log 中没有 output。 初学者问题

问题描述

1 个解决方案

解决方案1 0 2022-12-03 09:07:52

console.log 中没有 output。初学者问题

解决方案1
0 2022-12-03 09:07:52