JavaScriptで単語の先頭文字を大文字にする方法

split()とmap()を使用する方法:

function capitalizeFirstLetter(str) {
return str.split(' ').map(function(word) {
return word.charAt(0).toUpperCase() + word.slice(1);
}).join(' ');
}
var sentence = "uppercase first letter of each word";
var capitalizedSentence = capitalizeFirstLetter(sentence);
console.log(capitalizedSentence);
// 出力結果: "Uppercase First Letter Of Each Word"

正規表現とreplace()を使用する方法:

function capitalizeFirstLetter(str) {
return str.replace(/\b\w/g, function(l) {
return l.toUpperCase();
});
}
var sentence = "uppercase first letter of each word";
var capitalizedSentence = capitalizeFirstLetter(sentence);
console.log(capitalizedSentence);
// 出力結果: "Uppercase First Letter Of Each Word"

関数を使用する方法:

function capitalizeFirstLetter(str) {
var words = str.split(' ');
for (var i = 0; i < words.length; i++) {
words[i] = words[i].charAt(0).toUpperCase() + words[i].slice(1);
}
return words.join(' ');
}
var sentence = "uppercase first letter of each word";
var capitalizedSentence = capitalizeFirstLetter(sentence);
console.log(capitalizedSentence);
// 出力結果: "Uppercase First Letter Of Each Word"