Sourcemaps don't seem to be generated correctly

[wespickett]

Tested on a file utils.js with utils.js.map

Then used source-map-explorer utils.js utils.js.map (https://www.npmjs.com/package/source-map-explorer)
And I get this error:

source-map-explorer utils.js utils.js.map       

utils.js
  Your source map refers to generated column 9 on line 9, but the source only contains 1 column(s) on that line.
  Check that you are using the correct source map.

Verified the same result using https://www.npmjs.com/package/source-map with script sm.js

It expects line 9 to be the base64encode line, but base64encode is actually on line 7 in the generated code

[BinToss]

Using Packemon's experimental SWC compiler, the sourcemaps are correct...at first glance. I seem to only experience incorrect source maps when using the default Babel toolchain.

Edit: swc isn't right, either, according to source-map-explorer. But, in practice, it's more accurate than Babel's output; good enough for debugging.

npx source-map-explorer .\mjs\utils\reflection.mjs .\mjs\utils\reflection.mjs.map

Babel:

Your source map refers to generated column 229 on line 10, but the source only contains 228 column(s) on that line.
Check that you are using the correct source map.

Swc:

Your source map refers to generated column 63 on line 22, but the source only contains 62 column(s) on that line.
Check that you are using the correct source map.