The Velt Book#

The Book teaches Velt from the ground up, with an eye on what is new if you come from TypeScript. Every Velt code block in it is compiled by the documentation tests.

Getting started#

1. Getting started: install, your first program, project layout
2. A tour of Velt: the whole language in one page
3. Velt for TypeScript developers: every difference, and why

Guides#

• Building an HTTP server: routing, JSON, validation, shared state, tests
• Building a command-line tool: arguments, files, exit codes, tests
• Server-rendered pages with TSX: components, lists, layouts, async data, streaming
• Async and concurrency: promises, top-level await, timeouts, task scopes, spawn, shared state
• Error handling: typed catch, throws clauses, errors as values, panics
• Memory without a garbage collector: JavaScript's object semantics, deterministic freeing
• Modules and packages: organizing code, dependencies, publishing
• Packages with native code: a Rust crate inside a package
• Testing: velt test, describe/it/expect, kept results
• Hot reload with velt dev: edit a running server

When you need the precise rules, go to the Reference; for module APIs, to the standard library.