Question

Lorem ipsum dolor sit amet consectetur adipisicing elit.

Is it possible to use .replace to change everything beyond amet in the sentence above?

Answer 1

It is.

str.replace(/(amet).+$/, '$1FOO')

If "amet" actually contains weird characters, you have to ‘regex quote’ them: ., -, [ etc.

EDIT
Explaining regex is hard.

• (amet) => Capture a literal “amet”. Capture, because you want to keep that part for the replacement, because you want to replace everything after “amet”.
• .+ => Any type of characters (.), but at least one (+). If you want at least 0, you can use * instead of +.
• $ => the end of the subject (str). In thise case, it’s unnecessary, because regex is greedy and won’t stop until you tell it to (and since .+ will never stop matching, the end is the end)
• $1 => This is a placeholder for ‘the first match’. In this case, it’s awlways "amet", because we matched a literal "amet". If the regex is variable, this $1 will be unknown (which is what it exists for).
• FOO => Another literal (the replacement). Your question includes “… change everything after …” which – in my eyes – means “replace by "FOO"“.

Clear enough? If not, I’d be happy to try to explain better. Always a great resource (for young and old, wise and not-so-wise and pro’s and beginners): http://www.regular-expressions.info/

To conclude: regex is AWESOME.