是否有一个简单的方法来转换字符串标题大小写?例如,约翰·史密斯变成了约翰·史密斯。我不是在寻找像John Resig的解决方案那样复杂的东西,只是(希望)一些一两行代码。
当前回答
健壮的函数式编程方式做标题大小写函数
Exaplin版本
function toTitleCase(input){
let output = input
.split(' ') // 'HOw aRe YOU' => ['HOw' 'aRe' 'YOU']
.map((letter) => {
let firstLetter = letter[0].toUpperCase() // H , a , Y => H , A , Y
let restLetters = letter.substring(1).toLowerCase() // Ow, Re, OU => ow, re, ou
return firstLetter + restLetters // conbine together
})
.join(' ') //['How' 'Are' 'You'] => 'How Are You'
return output
}
实现版本
function toTitleCase(input){
return input
.split(' ')
.map(i => i[0].toUpperCase() + i.substring(1).toLowerCase())
.join(' ')
}
toTitleCase('HoW ARe yoU') // reuturn 'How Are You'
其他回答
一个使用lodash -的解决方案
import { words, lowerCase, capitalize, endsWith, padEnd } from 'lodash';
const titleCase = string =>
padEnd(
words(string, /[^ ]+/g)
.map(lowerCase)
.map(capitalize)
.join(' '),
string.length,
);
与其他答案相比,我更喜欢下面的答案。它只匹配每个单词的第一个字母,并将其大写。更简单的代码,更容易阅读和更少的字节。它保留了现有的大写字母,以防止扭曲的首字母缩写。然而,你总是可以首先在你的字符串上调用toLowerCase()。
function title(str) {
return str.replace(/(^|\s)\S/g, function(t) { return t.toUpperCase() });
}
你可以把这个添加到你的字符串原型,这将允许你'my string'.toTitle()如下所示:
String.prototype.toTitle = function() {
return this.replace(/(^|\s)\S/g, function(t) { return t.toUpperCase() });
}
例子: String.prototype.toTitle = function() { return this.replace(/(^|\s)\ s /g, function(t) {return t. touppercase ()}); } console.log('全部小写->','全部小写'.toTitle()); console.log('所有大写字母->','所有大写字母'.toTitle()); console.log("I'm a little teapot ->","I'm a little teapot".toTitle());
惊讶地看到没有人提到rest参数的使用。下面是一个简单的使用ES6 Rest参数的程序。
让我们看《约翰·史密斯》 str = str。劈(“”)。([firstChar文件夹,...休息)= > firstChar toUpperCase() +休息。加入toLowerCase()(“”)。加入(“”) 控制台日志(str)。
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.'));
如果你需要一个语法正确的答案:
这个答案考虑了介词,如“of”,“from”,… 输出将生成您希望在论文中看到的编辑风格的标题。
toTitleCase函数
考虑此处列出的语法规则的函数。 该函数还合并空格和删除特殊字符(根据需要修改regex)
const toTitleCase = (str) => {
const articles = ['a', 'an', 'the'];
const conjunctions = ['for', 'and', 'nor', 'but', 'or', 'yet', 'so'];
const prepositions = [
'with', 'at', 'from', 'into','upon', 'of', 'to', 'in', 'for',
'on', 'by', 'like', 'over', 'plus', 'but', 'up', 'down', 'off', 'near'
];
// The list of spacial characters can be tweaked here
const replaceCharsWithSpace = (str) => str.replace(/[^0-9a-z&/\\]/gi, ' ').replace(/(\s\s+)/gi, ' ');
const capitalizeFirstLetter = (str) => str.charAt(0).toUpperCase() + str.substr(1);
const normalizeStr = (str) => str.toLowerCase().trim();
const shouldCapitalize = (word, fullWordList, posWithinStr) => {
if ((posWithinStr == 0) || (posWithinStr == fullWordList.length - 1)) {
return true;
}
return !(articles.includes(word) || conjunctions.includes(word) || prepositions.includes(word));
}
str = replaceCharsWithSpace(str);
str = normalizeStr(str);
let words = str.split(' ');
if (words.length <= 2) { // Strings less than 3 words long should always have first words capitalized
words = words.map(w => capitalizeFirstLetter(w));
}
else {
for (let i = 0; i < words.length; i++) {
words[i] = (shouldCapitalize(words[i], words, i) ? capitalizeFirstLetter(words[i], words, i) : words[i]);
}
}
return words.join(' ');
}
确保正确性的单元测试
import { expect } from 'chai';
import { toTitleCase } from '../../src/lib/stringHelper';
describe('toTitleCase', () => {
it('Capitalizes first letter of each word irrespective of articles, conjunctions or prepositions if string is no greater than two words long', function(){
expect(toTitleCase('the dog')).to.equal('The Dog'); // Capitalize articles when only two words long
expect(toTitleCase('for all')).to.equal('For All'); // Capitalize conjunctions when only two words long
expect(toTitleCase('with cats')).to.equal('With Cats'); // Capitalize prepositions when only two words long
});
it('Always capitalize first and last words in a string irrespective of articles, conjunctions or prepositions', function(){
expect(toTitleCase('the beautiful dog')).to.equal('The Beautiful Dog');
expect(toTitleCase('for all the deadly ninjas, be it so')).to.equal('For All the Deadly Ninjas Be It So');
expect(toTitleCase('with cats and dogs we are near')).to.equal('With Cats and Dogs We Are Near');
});
it('Replace special characters with space', function(){
expect(toTitleCase('[wolves & lions]: be careful')).to.equal('Wolves & Lions Be Careful');
expect(toTitleCase('wolves & lions, be careful')).to.equal('Wolves & Lions Be Careful');
});
it('Trim whitespace at beginning and end', function(){
expect(toTitleCase(' mario & Luigi superstar saga ')).to.equal('Mario & Luigi Superstar Saga');
});
it('articles, conjunctions and prepositions should not be capitalized in strings of 3+ words', function(){
expect(toTitleCase('The wolf and the lion: a tale of two like animals')).to.equal('The Wolf and the Lion a Tale of Two like Animals');
expect(toTitleCase('the three Musketeers And plus ')).to.equal('The Three Musketeers and Plus');
});
});
请注意,我从提供的字符串中删除了相当多的特殊字符。您将需要调整正则表达式以满足项目的需求。