const regex = /[-._]|(?<=[a-z])(?=[A-Z])|(?<=[A-Z])(?=[A-Z][a-z])/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('[-._]|(?<=[a-z])(?=[A-Z])|(?<=[A-Z])(?=[A-Z][a-z])', 'gm')
const str = `allow-nonxdr-writes
io.native.lib.available
ha.zookeeper.parent-znode
min_file_size
ProxyStatus
ProxyFCGIBackendType
SessionDBDCookieRemove
DBDriver
SSLOCSPDefaultResponder
helloWorldABCdEF`;
const subst = ` `;
// 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