The keyboard with backspace

Problem

Sofia types on the bus, with one finger and a lot of bumps. The keyboard saves every key she presses, in order, including backspace, which is written down as #.

You get that log, a string that may be empty. Return what is left written at the end: each # erases the last character still written at that moment, and is never written itself. A # when nothing is written does nothing. Spaces are characters like any other.

With "cag#t" you return "cat": the g is erased and then the t comes. With "ab##c" you return "c", and with "##hello" you return "hello".

Examples

• Fixes one letter

  "cag#t" → "cat"

• Erases two in a row

  "ab##c" → "c"

• Erasing over nothing

  "##hello" → "hello"

• No keys

  "" → ""

• With spaces

  "see you latre##er" → "see you later"

Besides these, the challenge has hidden tests that are revealed when you submit your solution.

You start with this

def final_text(keys):
    pass

function finalText(keys) {
}