Remove trailing spaces automatically or with a shortcut

You can enable whitespace trimming at file save time from settings:

Open Visual Studio Code User Settings (menu File → Preferences → Settings → User Settings tab). Click the icon in the top-right part of the window. This will open a document. Add a new "files.trimTrailingWhitespace": true setting to the User Settings document if it's not already there. This is so you aren't editing the Default Setting directly, but instead adding to it. Save the User Settings file.

We also added a new command to trigger this manually (Trim Trailing Whitespace from the command palette).

Menu Code → Preference → Settings →

https://i.stack.imgur.com/hZrUY.png

Check the "Trim Trailing Whitespace" option - "When enabled, will trim trailing whitespace when saving a file".

Not only can you change the Visual Studio Code settings to trim trailing whitespace automatically, but you can also do this from the command palette (Ctrl+Shift+P):

https://i.stack.imgur.com/wmfl7.png

You can also use the keyboard shortcut:

Windows, Linux: Ctrl+K, Ctrl+X

Mac: ⌘ + k, ⌘ + x.

(I'm using Visual Studio Code 1.20.1.)

In recent Visual Studio Code versions you can find settings here:

Menu File → Preference → Settings → Text Editor → Files → (scroll down a bit) Trim Trailing Whitespace

This is for trimming whitespace when saving a file.

Or you can search "Trim Trailing Whitespace" in the top search bar.

Visual Studio Code, menu File → Preference → Settings → search for "trim":

https://i.stack.imgur.com/pVxe1.png

Have a look at the EditorConfig plugin.

By using the plugin you can have settings specific for various projects. Visual Studio Code also has IntelliSense built-in for .editorconfig files.

<Ctr>-<Shift>-<F> 

Format, does it as well.

This removes trailing whitespace and formats/indents your code.