index.js
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'use strict';
const UPPERCASE = /[\p{Lu}]/u;
const LOWERCASE = /[\p{Ll}]/u;
const LEADING_CAPITAL = /^[\p{Lu}](?![\p{Lu}])/gu;
const IDENTIFIER = /([\p{Alpha}\p{N}_]|$)/u;
const SEPARATORS = /[_.\- ]+/;
const LEADING_SEPARATORS = new RegExp('^' + SEPARATORS.source);
const SEPARATORS_AND_IDENTIFIER = new RegExp(SEPARATORS.source + IDENTIFIER.source, 'gu');
const NUMBERS_AND_IDENTIFIER = new RegExp('\\d+' + IDENTIFIER.source, 'gu');
const preserveCamelCase = (string, locale) => {
let isLastCharLower = false;
let isLastCharUpper = false;
let isLastLastCharUpper = false;
for (let i = 0; i < string.length; i++) {
const character = string[i];
if (isLastCharLower && UPPERCASE.test(character)) {
string = string.slice(0, i) + '-' + string.slice(i);
isLastCharLower = false;
isLastLastCharUpper = isLastCharUpper;
isLastCharUpper = true;
i++;
} else if (isLastCharUpper && isLastLastCharUpper && LOWERCASE.test(character)) {
string = string.slice(0, i - 1) + '-' + string.slice(i - 1);
isLastLastCharUpper = isLastCharUpper;
isLastCharUpper = false;
isLastCharLower = true;
} else {
isLastCharLower = character.toLocaleLowerCase(locale) === character && character.toLocaleUpperCase(locale) !== character;
isLastLastCharUpper = isLastCharUpper;
isLastCharUpper = character.toLocaleUpperCase(locale) === character && character.toLocaleLowerCase(locale) !== character;
}
}
return string;
};
const preserveConsecutiveUppercase = input => {
LEADING_CAPITAL.lastIndex = 0;
return input.replace(LEADING_CAPITAL, m1 => m1.toLowerCase());
};
const postProcess = (input, options) => {
SEPARATORS_AND_IDENTIFIER.lastIndex = 0;
NUMBERS_AND_IDENTIFIER.lastIndex = 0;
return input.replace(SEPARATORS_AND_IDENTIFIER, (_, identifier) => identifier.toLocaleUpperCase(options.locale))
.replace(NUMBERS_AND_IDENTIFIER, m => m.toLocaleUpperCase(options.locale));
};
const camelCase = (input, options) => {
if (!(typeof input === 'string' || Array.isArray(input))) {
throw new TypeError('Expected the input to be `string | string[]`');
}
options = {
pascalCase: false,
preserveConsecutiveUppercase: false,
...options
};
if (Array.isArray(input)) {
input = input.map(x => x.trim())
.filter(x => x.length)
.join('-');
} else {
input = input.trim();
}
if (input.length === 0) {
return '';
}
if (input.length === 1) {
return options.pascalCase ? input.toLocaleUpperCase(options.locale) : input.toLocaleLowerCase(options.locale);
}
const hasUpperCase = input !== input.toLocaleLowerCase(options.locale);
if (hasUpperCase) {
input = preserveCamelCase(input, options.locale);
}
input = input.replace(LEADING_SEPARATORS, '');
if (options.preserveConsecutiveUppercase) {
input = preserveConsecutiveUppercase(input);
} else {
input = input.toLocaleLowerCase();
}
if (options.pascalCase) {
input = input.charAt(0).toLocaleUpperCase(options.locale) + input.slice(1);
}
return postProcess(input, options);
};
module.exports = camelCase;
// TODO: Remove this for the next major release
module.exports.default = camelCase;