@hecto/compiler

A build-time backend for explicitly pure @hecto/fp pipelines, including environments where new Function is unavailable: strict Content Security Policy pages, most browser extensions, and some serverless runtimes.

The plugin statically detects pipe(input, ...steps) / flow(...steps) / compile(...steps) / compilePure(...steps) call sites whose every step is a call to a tracked @hecto/fp/array, /option, /result, or /record operator with statically-inspectable arguments, and replaces the call site with a hoisted, monomorphic function __hgFused_N(input, ...bindings) { ... } whose generated bindings are isolated from user bindings — the same loop/ladder shape @hecto/fp's own runtime codegen produces, generated at build time via @hecto/fp's emitSource. It never reimplements that emission logic itself.

Single-step ordinary composition may be lowered because it preserves callback count, order, and exceptions. Multi-step fusion requires compilePure, pipe/flow imported from @hecto/fp/fusion, or plugin { pure: true }. That explicit contract promises every callback is total, depends only on its arguments, and has no observable side effects. Anything outside the supported scope is left byte-identical and reported with a decline reason.

Usage

// vite.config.ts
import { hgFp } from '@hecto/compiler/vite'

export default {
  plugins: [hgFp({ diagnostics: 'warn' })],
}

Also available: @hecto/compiler/rollup, @hecto/compiler/esbuild, @hecto/compiler/webpack, and @hecto/compiler's raw export (an unplugin factory) for hosts that consume unplugin directly.

Options

• diagnostics: 'off' | 'warn' | 'error' (default 'warn') — 'warn' reports each declined site plus a build-end summary; 'error' throws at the first declined site.
• pure: boolean (default false) — declares every matched pipeline in the included files pure and enables multi-step fusion. Prefer compilePure or the /fusion entry for a per-site contract.
• include / exclude: file filters (default: JS/TS/JSX/TSX, excluding node_modules).

Testing without a bundler

transformHgPipelines(code, id, options) is exported as a pure function — call it directly to get { code, map, diagnostics } without going through any bundler.

Strict TypeScript consumers

The public adapter declarations use the native Vite, Rollup, esbuild and Webpack types. These four host packages are declared peers; install them with the compiler when your package manager does not install peers automatically. The typed adapter surface covers those four hosts and the concrete raw factory. Other unplugin adapter properties remain available at runtime for compatibility.