For anyone interested in reading more about it, Stack Overflow user kangax has written an incredibly in-depth blog post about the delete statement on their blog, Understanding delete. It is highly recommended.
If you'd like a new object with all the keys of the original except some, you could use the destructuring.
Demo
let myObject = {
"ircEvent": "PRIVMSG",
"method": "newURI",
"regex": "^http://.*"
};
const {regex, ...newObj} = myObject;
console.log(newObj); // has no 'regex' key
console.log(myObject); // remains unchanged
Best Solution
Docs.
For all occurrences to be discarded use:
PS: The replace function returns a new string and leaves the original string unchanged, so use the function return value after the replace() call.