不使用正则表达式，仅供参考:

String.prototype.toProperCase = function() { Var =这个。分割(' '); Var结果= []; For (var I = 0;I < words.length;我+ +){ var letter = words[i].charAt(0).toUpperCase(); 结果。Push(字母+单词[i].slice(1)); ｝ 返回的结果。加入(' '); }; console.log ( “约翰·史密斯”.toProperCase () ）

这个解决方案将标点符号考虑到新句子中，处理引用，将小词转换为小写，忽略首字母缩写或全大写单词。

var stopWordsArray = new Array("a", "all", "am", "an", "and", "any", "are", "as", "at", "be", "but", "by", "can", "can't", "did", "didn't", "do", "does", "doesn't", "don't", "else", "for", "get", "gets", "go", "got", "had", "has", "he", "he's", "her", "here", "hers", "hi", "him", "his", "how", "i'd", "i'll", "i'm", "i've", "if", "in", "is", "isn't", "it", "it's", "its", "let", "let's", "may", "me", "my", "no", "of", "off", "on", "our", "ours", "she", "so", "than", "that", "that's", "thats", "the", "their", "theirs", "them", "then", "there", "there's", "these", "they", "they'd", "they'll", "they're", "they've", "this", "those", "to", "too", "try", "until", "us", "want", "wants", "was", "wasn't", "we", "we'd", "we'll", "we're", "we've", "well", "went", "were", "weren't", "what", "what's", "when", "where", "which", "who", "who's", "whose", "why", "will", "with", "won't", "would", "yes", "yet", "you", "you'd", "you'll", "you're", "you've", "your");

// Only significant words are transformed. Handles acronyms and punctuation
String.prototype.toTitleCase = function() {
    var newSentence = true;
    return this.split(/\s+/).map(function(word) {
        if (word == "") { return; }
        var canCapitalise = true;
        // Get the pos of the first alpha char (word might start with " or ')
        var firstAlphaCharPos = word.search(/\w/);
        // Check for uppercase char that is not the first char (might be acronym or all caps)
        if (word.search(/[A-Z]/) > 0) {
            canCapitalise = false;
        } else if (stopWordsArray.indexOf(word) != -1) {
            // Is a stop word and not a new sentence
            word.toLowerCase();
            if (!newSentence) {
                canCapitalise = false;
            }
        }
        // Is this the last word in a sentence?
        newSentence = (word.search(/[\.!\?:]['"]?$/) > 0)? true : false;
        return (canCapitalise)? word.replace(word[firstAlphaCharPos], word[firstAlphaCharPos].toUpperCase()) : word;
    }).join(' ');
}

// Pass a string using dot notation:
alert("A critical examination of Plato's view of the human nature".toTitleCase());
var str = "Ten years on: a study into the effectiveness of NCEA in New Zealand schools";
str.toTitleCase());
str = "\"Where to from here?\" the effectivness of eLearning in childhood education";
alert(str.toTitleCase());

/* Result:
A Critical Examination of Plato's View of the Human Nature.
Ten Years On: A Study Into the Effectiveness of NCEA in New Zealand Schools.
"Where to From Here?" The Effectivness of eLearning in Childhood Education. */

ES-6 way to get title case of a word or entire line.
ex. input = 'hEllo' --> result = 'Hello'
ex. input = 'heLLo woRLd' --> result = 'Hello World'

const getTitleCase = (str) => {
  if(str.toLowerCase().indexOf(' ') > 0) {
    return str.toLowerCase().split(' ').map((word) => {
      return word.replace(word[0], word[0].toUpperCase());
    }).join(' ');
  }
  else {
    return str.slice(0, 1).toUpperCase() + str.slice(1).toLowerCase();
  }
}

如果可以的话，我强烈建议使用开源的NPM包，这个包在typescript中工作得很好:

NPM: https://www.npmjs.com/package/title-case

Github: https://github.com/blakeembrey/change-case/tree/master/packages/title-case readme

运行npm install title-case将包添加到项目中。

使用标题大小写npm包的示例代码:

import { titleCase } from "title-case";

titleCase("string"); //=> "String"
titleCase("follow step-by-step instructions"); //=> "Follow Step-by-Step Instructions"

如果一个CSS解决方案满足你的需求，你可以应用文本转换CSS样式到你的控件:

text-transform: capitalize;

请注意，这将会改变: hello world到hello world HELLO WORLD到HELLO WORLD(不变) emily-jane o'brien致emily-jane o'brien(不正确) 玛丽亚·冯·特拉普写给玛丽亚·冯·特拉普(不正确)

我的清单是基于三个快速搜索。一个用于不大写的单词列表，一个用于完整的介词列表。

最后一个搜索建议，5个或5个字母以上的介词应该大写，这是我喜欢的。我的目的是非正式使用。我把“without”留在了他们的单词里，因为它是with的明显对应词。

所以它把首字母缩写，标题的第一个字母，以及大多数单词的第一个字母都大写。

它不打算处理带有大写锁的单词。我不想管这些。

function camelCase(str) { return str.replace(/((?:^|\.)\w|\b(?!(?:a|amid|an|and|anti|as|at|but|but|by|by|down|for|for|for|from|from|in|into|like|near|nor|of|of|off|on|on|onto|or|over|past|per|plus|save|so|than|the|to|to|up|upon|via|with|without|yet)\b)\w)/g, function(character) { return character.toUpperCase(); })} console.log(camelCase('The quick brown fox jumped over the lazy dog, named butter, who was taking a nap outside the u.s. Post Office. The fox jumped so high that NASA saw him on their radar.'));