Smart Replacing Expletives

index.js

console.log("\n\n-------------");

const isUpperCase = (m)=> (m == m.toUpperCase()),
	isLowerCase = (m) => (m == m.toLowerCase());
const isArr = Array.isArray;

class VjuhSwear {

	constructor(text) {
		this.text = text;
	}

	// Обычная замена
	v(swearRegex, word) {

		var re = new RegExp("([^а-яё]|^)("+swearRegex+")(?=[^а-яё]|$)", "gi");
		
		// console.log(re);

		var res = this.text.replace(re, function( full, m1, m2 ) {

			console.log("full:", full);
			console.log("m1:", m1);
			console.log("m2:", m2);
			console.log("arguments:", arguments);

			if ( m2.charAt(0).toUpperCase() == m2.charAt(0) ) {
				return m1 + word.charAt(0).toUpperCase() + word.slice(1);
			}
			else {
				return m1 + word;
			}

		});

		return res;
	}

	// Smart
	// [ "б", "л", "я" ],	[ "б", "лэнч" ]
	s(swearArr, word) {
		var ms = swearArr.map(s=> ( "("+s+")+" ) ).join("");

		var re = new RegExp("([^а-яё]|^)"+ms+"(?=[^а-яё]|$)", "gi");
		
		console.log(re);

		var res = this.text.replace(re, function( full, m1, m2 ) {

			if(isUpperCase(m2)) {
				return m1 + word[0].toUpperCase() + word.join("").slice(1);
			}
			else
				return m1 + word.join("");

		});

		return res;
	}
}



var vj = new VjuhSwear("та ББллляяяЯяЯ, как так таа");

var repl = ["б", "л", ["э"], "нч"];

// var t = vj.v("(б)+(л)+(я)+(\\s|^|\"|,|!|\\?|.|)", repl);
var t = vj.s([ "б", "л", "я" ], repl);

console.log("t:", t);

// var t2 = vj.v("(\\s|^|\"|«|\\()бл(я)+(\\s|^|\"|,|!|\\?|.|)", "блэнч");
// console.log("t2:", t2);