edilsonborges

const regex = /([$][a-z]*)[_]([a-z])([a-z]*)/g;
const str = `\$bo_ativo`;
const subst = `$1\U$2\E$3`;

// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);

console.log('Substitution result: ', result);