How to set web-mode to use single-line comment style instead of multi-line for JavaScript

Question

When commenting C-style code like C++, JavaScript etc., I use single-line comments to be able to uncomment a previously commented region selectively, i.e

// This 
// is
// a single-line style
// comment

If I later want to uncomment lines 2 and 3, for example, I would simply select them and uncomment. With multi-line comments /* */, however, I would first need to uncomment the whole block, then selectively comment the parts excluding those that I wanted to uncomment in the first place. From this question, I found out that I can change the comment character to // by putting in my config

(setq-default web-mode-comment-formats (remove '("javascript" . "/*") web-mode-comment-formats))
(add-to-list 'web-mode-comment-formats '("javascript" . "//"))

This, however, does not change the commenting behavior of web-mode. When I select the desired region and run web-mode-comment-or-uncomment-region, it still exhibits multi-line behavior and uncomments the whole block instead of the region that I select.

How can I uncomment just the selected region instead of the whole block?

Answer 1

It could be that web-mode-comment-formats is not defined when emacs is initialized and thus removes nothing from it at that stage, in my case web-mode is loaded only on demand so trying to customize it at that point doesn't make sense. Try to do that customization in a web-mode-hook or set explicitly the values you need in that list:

(setq web-mode-comment-formats '(("typescript" . "//")
                                 ("javascript" . "//")
                                 ("java" . "//"))