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This article mainly explains "how to capitalize the first letter of a string in JS". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "how to capitalize the first letter of a string in JS"!

1. For cycle

Var a ='Hi, my name\'s Han Meimei, a SOFTWARE engineer'

/ / for loop

Function titleCase (s) {

Var I, ss = s.toLowerCase () .split (/\ slots /)

For (I = 0; I)

< ss.length; i++) { 　　ss[i] = ss[i].slice(0, 1).toUpperCase() + ss[i].slice(1); 　　} 　　return ss.join(‘ ‘); 　　} 　　console.log(titleCase(a)); 　　2、For循环+replace 　　//for循环+replace 　　function titleCase1(str) { 　　//将字符串分解为数组并将其小写化 　　var convertToArray = str.toLowerCase().split(" "); 　　for (var i = 0; i < convertToArray.length; i++) { 　　var char = convertToArray[i].charAt(0); 　　//使用 replace()方法将数组中的每个首字母大写化 　　convertToArray[i] = convertToArray[i].replace(char, function replace(char) { 　　return char.toUpperCase(); 　　}); 　　} 　　return convertToArray.join(" "); 　　} 　　console.log(titleCase1(a)); 　　1与2写法差别不大 　　3、正则+replace 　　//正则+replace 　　function titleCase2(s) { 　　return s.toLowerCase().replace(/\b([\w|‘]+)\b/g, function(word) { 　　//return word.slice(0, 1).toUpperCase() + word.slice(1); 　　return word.replace(word.charAt(0), word.charAt(0).toUpperCase()); 　　}); 　　} 　　console.log(titleCase2(a)); 　　思路：用正则将字符串拆分为单词数组，并对每个单词进行首字母大写处理。这里简单的把字母、数字、下划线和单撇号都视为了单词成员。 　　4、数组+map 　　//数组+map 　　function titleCase3(s) { 　　return s.toLowerCase().split(/\s+/).map(function(item, index) { 　　return item.slice(0, 1).toUpperCase() + item.slice(1); 　　}).join(‘ ‘); 　　} 　　console.log(titleCase3(a)); 　　思路：根据空白将字符串拆分为数组，对每个单词进行首字母大写处理，并将所有处理后的结果组成一个新数组然后拼接成字符串。 　　5、数组+reduce 　　//数组+reduce 　　function titleCase4(s) { 　　return s.toLowerCase().split(/\s+/).reduce(function(prev, item, array, array) { 　　return prev + (prev.trim() && ‘ ‘) + item.slice(0, 1).toUpperCase() + item.slice(1); 　　}, ‘‘); 　　} 　　console.log(titleCase4(a)); 　　思路：根据空白将字符串拆分为数组，对每个单词进行首字母大写处理，并将所有处理后的结果连成一个新字符串。 　　6、ES6写法 　　//ES6写法 　　function titleCase5(str) { 　　return str.toLowerCase().replace(/( |^)[a-z]/g, (L) =>

L.toUpperCase ()

}

Console.log (titleCase5 (a))

Idea: replace the first letter of each word with uppercase with rules.

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