Use the node.exe --preserve-symlinks switch in your launch configuration runtimeArgs attribute.
Note that this won't work if the debugger is launched via npm:
// .vscode/launch.json
{
"request": "launch",
"runtimeExecutable": "npm"
}
This is because the --preserve-synlinks argument would be passed to npm instead of to node.
In such cases, the env attribute may be used, setting NODE_PRESERVE_SYMLINKS to 1, but note that this won't work if node is not the first command in the npm script being run (e.g., do something && node).
