Visual Studio 2017 does not show collapse icon for js file

Question

Visual studio 2017 does not show function collapse icon for JS files. However, it highlights function and variable keywords.

Answer 1

You can enable 'outling' (as it's called) for the current document by selecting the "Outlining" item from the "Edit" menu, and choosing "Start Automatic Outlining," as shown below:

In theory, there should be a "global" setting for this, like there is for other languages (eg Options -> Text Editor -> C# -> Advanced then "Enter Outlining mode when files open") but, for JavaScript, this seems to be a 'bug' in the current release: see this Developer Community post.