javascript - JavaScript 输出字符串而不是未定义？

Question

在返回答案时，我得到的是 undefined 而不是 String - 尽管它是正确的正确字符被记录。如何让它输出一个明确的字符串？

var greet = function(name) {
   let  first = String(name. charAt(0). toUpperCase());
    let second = String(name.slice(1));

    console.log('Hello ' + first + second + '!');
    }

标签： javascript

Answer 1

你忘了返回一个值，所以返回值是undefined.

var greet = function(name) {
    let  first = String(name. charAt(0). toUpperCase());
    let second = String(name.slice(1));

    return 'Hello ' + first + second + '!';
}

console.log(greet('Gemma'));