jQuery for（x in y）循环

Question

在下面的代码中，变量“key”没有大写，即使任何其他变量（如steve [j]）如果在调用中替换“key”时也会大写。函数capitaliseFirstLetter()。

有人可以告诉我为什么吗？

for(key in aray) {
    steve = aray[key];
    for(j = 0; j < steve.length; j++){
        diff = steve[j].slice(key.length);
        if(diff == ""){
            diff = "_";
        }
        diffs.push(diff);
        var firstLetterUpper = /^[A-Z]/.test(steve[j]);
        if(firstLetterUpper){
            capitaliseFirstLetter(key)
            alert(key])
        }

    }
}
function capitaliseFirstLetter(string){
    return string.charAt(0).toUpperCase() + string.slice(1);
}

Answer 1

key = capitaliseFirstLetter(key)
alert(key)

字符串对象按值传递给函数。所以它不会改变你应该重新分配价值

Answer 2

如果您的目标是捕获每个单词，可以更简单地完成：

JSFiddle：http://jsfiddle.net/UgT3x/

for (key in aray) {
    var steve = aray[key];
    console.log(toTitleCase(steve));
    // if you want to change the aray value
    aray[key] = toTitleCase(steve);
}

function toTitleCase(str) {
    return str.replace(/\w\S*/g, function (txt) {
        return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();
    });
}