From @mlewand on April 29, 2017 14:4

• VSCode Version: Code - Insiders 1.12.0-insider (0bec115, 2017-04-28T18:57:52.518Z)
• OS Version: Windows_NT ia32 10.0.15063
• Extensions: none

Steps to Reproduce:

1. Set a following option in your user/workspace settings:
   "javascript.format.insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis": true
2. Open a new file, set language to JavaScript.
3. Paste a following snippet:

foo( () => 1 );
foo( 1 );

1. Press ctrl/cmd+shift+f.

Expected

The code stays the way it is.

Actual

Initial space gets removed.

foo(() => 1 );
foo( 1 );

Additional Info

Checked also on a regular VSCode installation.

Copied from original issue: microsoft/vscode#25669