Using source map doubles memory usage

[ninja-]

Running app after compiling with -s option uses ~ 320MB on start, while without the flag it's 150-200MB.
Running pure typescript compiled version, even with require('source-map-support'), does not have this problem

[ninja-]

I did a test, replaced the custom source map require in index.js with regular require('source-map-support')
It makes the map lazy load at least, but on the first Error printed memory usage jumps from 120MB to 360MB :/ 280MB after some GC

[ninja-]

Using

nosources-source-map as devtool seems like a much better choice, it provides line numbers and original files but without using all the source code that you're not going to use anyway without chrome debugger.
It doesn't seem to help that much with mem usage though...but map is now 30% previous size

[ninja-]

I tried to use nodejs native integration --enable-source-maps instead, and it seems to work better.
But still, when it tries to read the sourcemap there is big memory usage jump - but at least it later garbage collects the map...
It would probably be best if ncc split compiled app to 10 files, then having sourcemaps 10% the size probably wouldn't be such a problem.

[styfle]

Now that --enable-source-maps is stable and supported back to Node.js 12, we could probably avoid the legacy polyfill used to support older versions of node and instead instruct the user to run node --enable-source-maps dist/index.js if they want source map support at runtime.

[ninja-]

yes native source map seems fine, but the key is to split index.js into chunks otherwise the sourcemap would get super big and take a ton of memory when loaded

[styfle]

The purpose of ncc is to bundle chunks of js into a single file. So splitting doesn't make sense, you could just avoid using ncc and keep the original files.

[ninja-]

I disagree with that, having index.js automatically split into 10 chunks and required in main index.js would serve the same purpose as currently but would fix the issues with source maps.
Could at least be a config option