const regex = /\[([^\]]+)\]\(([^)]+(.md))\)/gmi;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('\\[([^\\]]+)\\]\\(([^)]+(.md))\\)', 'gmi')
const str = `[test](test.md) [test](test.md) [test](test.md)
- [Standard Rewards](Standard%20Rewards.md)
- [Highest Exp Char](Exp%20Char.md)
- [Highest Exp Fairies](Crystals%20Fairy%20Exp.md)`;
const subst = `$3`;
// 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