Include working sourcemaps in dist

FullCalendar includes sourcemaps but there are multiple problems that prevent them from being useful, especially with file-based debuggers like VSCode:

• the copyright/license banner added by gulp to the bundle file after sourcemaps are generated throws off line numbering
• the original TS source files are not included in FullCalendar npm packages. This means that file-based debuggers like VSCode won’t be able to fully use debugging features, like setting breakpoints on FullCalendar files when the debugger is not running.
• even if the files were installed, the sources array in the sourcemap points to paths that don’t exist when FullCalendar is installed from npm, which will also break VSCode debugging. For example, below is the first few lines of the 4.2 sourcemap (https://unpkg.com/@fullcalendar/core@4.2.0/main.js.map), showing paths like "../../src/core/util/dom-manip.ts" that point to the build-time paths, not real paths under the npm install directory of any FullCalendar package.

{  
   "version":3,
   "file":"main.js",
   "sources":[  
      "../../src/core/util/dom-manip.ts",
      "../../src/core/util/geom.ts",
      "../../src/core/util/scrollbars.ts",
      "../../src/core/util/dom-geom.ts",
      "../../src/core/util/dom-event.ts",

To repro:

1. Using VSCode, open any app that installed FullCalendar from npm
2. Debug the app, setting a breakpoint in app code that calls into FullCalendar
3. Step into that call. You might have to Step Into several times to get past the module-loading shims.

Expected: Debugger shows the first line of the method in the original TS source file Actual: Debugger shows a line in a transpiled JS file. If you manually copy source files into the folders expected by the sourcemap, then the debugger will show the wrong line in a TS file.

I’ve built a PR that will address these problems. Will file it shortly.

P.S. - to clarify, sourcemaps for debugging FullCalendar itself (for contributors) probably work just fine. The problem is when developers who use FullCalendar as a dependency want to debug into it.

[arshaw]

v5, which has just been officially release now has working sourcemaps for all packages

[arshaw]

this is now working in v5-beta3! info on the release: https://fullcalendar.io/blog/2020/05/react-ts-v5-beta