Speed up Eclipse by excluding node_modules from validation

When developing Node software with Eclipse the JavaScript editor may feel slow, for example when copy/pasting source code.

This may be caused by the JavaScript validator checking all project files, including those in the node_modules folder. Depending on the number of external modules this may include hundreds of files, and checking them all constantly can have a big impact on performance. At least that's what I noticed in the Progress view.

Since files in the node_modules folder are external dependencies they don't have to be checked when editing your own code.

To make the validator skip files in this folder modify the JavaScript Include Path in the Project properties and exclude the complete node_modules folder.

For me, this made the JavaScript editor in Eclipse must more responsive when working on Node software.