Debugging with smartstep is super slow.

[v-pavanp]

Testing: #4954

• VSCode Version: 1.1.0-alpha
• OS Version: Windows10

Steps to Reproduce:

1. Create Basic nodejs JavaScript express3 project from Visual studio.
2. Launch VS code and open project folder.
3. update launch.json and set the value for smartstep:"true" and sourcemap: "true"
4. Start debugging and verify application behavior.

Note: I tried with all the possible combination of smartstep and sourcemap and observed this behavior when both the properties set to true.

Actual: Debugging is super slow and taking long time to render page.
Expected: Debugging should not be slow down when user enable smartstep.

[weinand]

@v-pavanp 'smart step' makes only sense if your project is using source maps and those sourcemaps cover most of the source code of the project. It seems your project is a plain JavaScript project without a single source map. Why would you use 'smart step' in this case? Just to be slower?

[v-pavanp]

No, but how about mixed TypeScript and JavaScript projects.

[weinand]

Mixing works fine as long as the JavaScript you are stepping through is reasonable small (for instance because it is just glue code generated by a transpiler).

If you have lots of JavaScript that does not map to some source language, using this option makes you slow because node debug has to single-step through the JavaScript.

So the slowness you are seeing is expected and not a bug.