Delete white space around insertion point in emacs

A while ago I discovered M-\ deletes white space between point and text.
Now I just discovered M-spc replaces tabs and spaces around point with just 1 space.
M-SPC runs the command just-one-space, which is an interactive
compiled Lisp function in `simple.el'.
It is bound to M-SPC.
(just-one-space &optional N)
Delete all spaces and tabs around point, leaving one space (or N spaces).
If N is negative, delete newlines as well.