Make sure you run npm i command in the project's dir before you begin, it'll install all dev dependencies. You'll also need to init git submodules:
$ npm i
$ git submodule init
$ git submodule updateCurrently code coverage is 100%, so new tests are essential when you add new functionality. There're several npm tasks which you can find useful:
npm testruns testsnpm run lintruns js linternpm run coverageruns code coverage task and generates a reportnpm run benchmarkruns performance benchmark
One pull request per one feature, nothing unusual.