@weftjs/ir

The Template IR: sealed, versioned templates, their effects, and the renderer that fills them.

Part of weft, a TypeScript fullstack framework that negotiates the wire form of a piece of UI per request. Applications import @weftjs/core; this package is what the compiler writes and what every other layer reads.

npm install @weftjs/ir

What it is

A compiled fragment is data, not a function. That single decision is why rendering a component ten times adds ten items of content and no template, why a delta can address a hole directly with nothing to reconcile, and why a template can be shipped once and kept resident on a client across visits.

The package holds the IR types, the sealing and versioning rules, the effect sets a fragment carries, and the renderer that turns pre-encoded byte segments into a response — measured at 1.4–1.96× a string-concatenating SSR of the same templates.

Version

The IR is a versioned specification. A minor is additive and must round-trip; a major is a wire break and refuses rather than migrates. Both rules are in spec/VERSIONING.md, and the format itself is in spec/ir/template-ir-2.md.

License

MIT