NPM task runner

I'm trying to make my own projects development tool using serveral NPM packages and running them via CLI configured in package.json. The last functionality I need to achieve is to watch specific directory for changes in my project folder and run specified task (like 'npm run compress-svg'). For example, in my project is svg folder, I need to watch that folder for changes and run npm task 'npm run compress-svg' when the folder changes. How can I achieve that functionality (maybe using another NPM package)?

via Simon