What does the front-end tooling and build infrastructure look like in your JavaScript based project?

What does your project setup look like? What's your build process, testing methodology, project structure etc?

• Do you use gulp/grunt?
• Do you use Chai/Mocha/Sinon etc for tests?
• How do you deploy the code?
• What build steps do you have?

and any other detail you can share. I am just a curious learner trying to grasp details of JavaScript based projects and tooling support.