Javascript covers all major areas in Application Development today.
Granted that there are already entrenched platforms in each of these
areas but what Javascript provides is a break from the past.

The Web Community has reinvented itself about 4 times so far, all
with similar technologies. It seems Software Projects are rewritten
every 5 years.

There seems to be only one area where Javascript has no ground,
namely high performance computing. C++ is still the best for that
scenario.

Web Design

sass, postcss, less, webcomponents

Deployment

shipit, gulp

Package Management

npm, bower

API Server

Express

No SQL Scripting

MongoDB, CouchDb

Data Format

JSON

Language Design

webassembly, transpilers, babel

Web App

openwebplatform

P2P

Webtorrents

Mobile App

nativescript, phonegap, react-native

Desktop App

Electron, nw.js

IDE

Atom

Workflows

Noflo, NodeRed

Command Line Applications

optimist, colors, cliff, inquiry, prompt

Embedded Scripting and IOT

cyclon.js, jerryscript

Game Development and Creative Programming

webgl, d3, tangle, processing.js, timbre.js, fabric, paper.js,
three.js

CMS

Ghost

Virtual Reality

mozillavr

Static Web Pages

Hexo

Privacy and Encryption

OpenPGP.js