The IntelliJ is opensource (jetbrains.org) - you can download it without any registration and use it for free. Not all features, however, are available in the community edition. These are very good news - especially for the adoption in the enterprise sector.
Web Apps, SPA, PWA with vanilla Java Script (ES 6+), CSS 3 and WebStandards only. As simple as possible, but not simpler. See you at: (Progressive) Web apps, Single Page Apps and WebStandards airhacks workshops at MUC airport, Winter Edition
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