package.json allows you to run npm packages locally."karma": "karma" script references the karma shell script is the node_modules/.bin directory. This reference needs to be grab and an alias needs to be applied to it in order to be used in other npm scripts, such as "test": "karma start".prepublish: Run before the package is publishedpublish, postpublish: Run after the package is publishedpreinstall: Run before the package is installedinstall, postinstall: Run after the package is installedpreversion, version: Run before bump the package versionpostversion: Run after bump the package versionpretest, test, posttest: Run by the npm test commandprestop, stop, poststop: Run by the npm stop commandprestart, start, poststart: Run by the npm start commandprerestart, restart, postrestart: Run by the npm restart command. Note: npm restart will run the stop and start scripts if no restart script is provided.It can be deduced that the "scripts" property in package.json is a very powerful tool. It can be used as a build tool, similar to the likes of Grunt and Gulp, but with over 250,000 packages available. NPM scripts runs npm packages installed locally to your project from the node_modules/.bin directory.