const matchStrInStrings = (str, signStr) => { const regExp = new RegExp(String(signStr), 'g'); const idxArr = []; let result; while((result = regExp.exec(str)) !== null) { let index = result.index; idxArr.push(index) } return idxArr; }
matchStrInStrings('abcabccbajj', 'a'); // [0, 3, 8] matchStrInStrings('abcabccbajj', 'ab'); // [0, 3] matchStrInStrings('abcabccbajj', 'cc'); // [5]