awesome-string
Version:
The ultimate JavaScript string library
38 lines (37 loc) • 1.31 kB
JavaScript
import { REGEXP_COMBINING_MARKS, REGEXP_SURROGATE_PAIRS } from 'helper/reg_exp/const';
import coerceToString from 'helper/string/coerce_to_string';
/**
* Reverses the `subject` taking care of
* <a href="https://rainsoft.io/what-every-javascript-developer-should-know-about-unicode/#24surrogatepairs">surrogate pairs</a> and
* <a href="https://rainsoft.io/what-every-javascript-developer-should-know-about-unicode/#25combiningmarks">combining marks</a>.
*
* @function reverseGrapheme
* @static
* @since 1.0.0
* @memberOf Manipulate
* @param {string} [subject=''] The string to reverse.
* @return {string} Returns the reversed string.
* @example
* as.reverseGrapheme('summer');
* // => 'remmus'
*
* as.reverseGrapheme('𝌆 bar mañana mañana');
* // => 'anañam anañam rab 𝌆'
*/
export default function reverseGrapheme(subject) {
let subjectString = coerceToString(subject);
/**
* @see https://github.com/mathiasbynens/esrever
*/
subjectString = subjectString
.replace(REGEXP_COMBINING_MARKS, function($0, $1, $2) {
return reverseGrapheme($2) + $1;
})
.replace(REGEXP_SURROGATE_PAIRS, '$2$1');
let reversedString = '';
let index = subjectString.length;
while (index--) {
reversedString += subjectString.charAt(index);
}
return reversedString;
}