Live geek or die tryin'

Why Are Trailing Whitespaces Bad

Whenever I see a trailing whitespace, my teeth gnash and I realize that some people just want to see the world burn.

Trailing whitespaces suck, please, don’t use them and ask your code editor to highlight them. Below are some reasons why.

Revision control systems and diff tools

This is the most important point.
For a diff tool, basically the thing used by CVS to detect code changes, this code:

function updateRepositoriesList($scope, Repository) {

Is not the same as:

function updateRepositoriesList($scope, Repository) {..

This, along with wrong indentation or using tabs instead of spaces, leads to unnecessary conflicts and is annoying when merging commits.

Moving inside the code

When I tell my editor to go to the end of the line, I obviously mean the end of the meaningful code, not some spaces after it.

Code display inside editors

On editors that wrap long lines, such as VIM, few spaces at the end of the line may lead to a useless line wrap.

function updateRepositoriesList($scope, Repository) {..|
...                                                    |
    loadingAnimation('show');                          |

Other reasons

Additional spaces increase the file size

That’s a very important point… If you store your code on floppy disks.

The parser will have to skip an extra character when compiling

Yet another important point. When coding on a Intel 8086 processor.

How to fight trailing whitespaces

By correctly configuring your editor

Highlighting them

If you don’t use VIM, skip this part.

If you do, add set list to your .vimrc, this will display unprintable characters such as our lovely trailing whitespaces and non-breaking spaces.
You can customise the characters used for that purpose thanks to the listchars command:

set listchars=trail:◃,nbsp:•

Wiping them

By searching and replacing them: %s/\s\+$//g.

I personally created a function that does the dirty work for me:

function! FutureShock()
  silent! %retab        " Replace tabs by spaces
  silent! %s/\%u00a0/ / " Replace nbsp by spaces
  silent! %s/\s\+$//    " Replace twsp by spaces

And mapped it to <LEADER>f:

map <LEADER>f :call FutureShock()<CR>

Future Shock is a Stratovarius song.

Check my VIM configuration for more awesome commands.

By looking for them before you commit

You review your code before committing it, don’t you? ;)
Thanks to the Git diff tool, you can clearly see trailing whitespaces highlighted in red when using git diff; git show, or git add -p (among others).

You now have no excuse for having these abominations in your code.