const regex = /(\[\[[^,\[\]]*?)(\s*),(\s*)/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(\\[\\[[^,\\[\\]]*?)(\\s*),(\\s*)', 'gm')
const str = `a, a
[[scsdfs , asdasda]]
[[vwdfwffwq]], [[vbsdfgv , gewgfwfgw,gewgw]]`;
const subst = `\1]], [[`;
// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions