solar-spa/CHANGELOG.md

Changelog

2.0.0

Complete rewrite. The source is now TypeScript, compiled by tsup to dual CJS/ESM with generated declarations. The WASM binary and build pipeline are all new.

Breaking Changes

• The default export is now an async function named spa() with a different signature. The old spa(date, lat, lon, elev, temp, pressure, refraction) positional API is replaced by spa(date, lat, lon, options) where options is an object.
• Return field solar_noon is now suntransit (matches the NREL SPA spec naming).
• Return field azimuth is now the navigational azimuth (eastward from north). The astronomical convention (westward from south) is available as azimuth_astro.
• New return fields: azimuth_astro, eot, error_code.
• Non-zero SPA error codes now throw an Error instead of returning silently.
• Invalid inputs (non-Date, non-finite coordinates, out-of-range values) now throw TypeError or RangeError before reaching the WASM layer.
• CJS entry point moved from ./solar-spa.js to ./dist/index.cjs.
• Minimum Node.js version is now 20.

Added

• TypeScript source (src/index.ts, src/types.ts) with full type safety.
• Dual CJS/ESM output via tsup: dist/index.cjs and dist/index.mjs.
• Generated TypeScript declarations for both formats: dist/index.d.ts (CJS) and dist/index.d.mts (ESM).
• Input validation with descriptive TypeError and RangeError messages.
• spaFormatted() function that returns sunrise, sunset, and transit as HH:MM:SS strings. Returns "N/A" during polar day or polar night.
• formatTime() utility for converting fractional hours to time strings. Handles negative values and 24-hour overflow.
• init() function for optional eager WASM initialization. Retries on failure instead of caching a rejected promise.
• SPA function code constants (SPA_ZA, SPA_ZA_INC, SPA_ZA_RTS, SPA_ALL) exported as const types.
• SpaFunctionCode union type for the function option.
• Options object with named parameters: timezone, elevation, pressure, temperature, delta_ut1, delta_t, slope, azm_rotation, atmos_refract, function.
• Automatic timezone detection from the Date object when timezone is omitted.
• Named OFFSET constant for WASM struct byte offsets (replaces magic numbers).
• Test suite with 68 ESM assertions and 13 CJS assertions covering multiple locations, seasons, input validation, concurrent calls, boundary coordinates, polar regions, all function codes, and formatTime edge cases.
• 100-scenario validation suite (validate.mjs) covering 20 cities worldwide, boundary conditions, polar regions, time edge cases, all function codes, atmospheric variations, and historical dates from 2000 BCE to 6000 CE. Includes throughput benchmarks.
• GitHub Actions CI workflow (Node 20/22/24 matrix with type checking).

Fixed

• onRuntimeInitialized race condition that caused the module to break after the first call. The v1 wrapper re-assigned the one-shot callback on every invocation, so only the first call ever resolved.
• WASM file path resolution failures in Webpack, Vite, and Next.js. The binary is now inlined as base64 via Emscripten's SINGLE_FILE flag, so there is no .wasm file to resolve at runtime.
• cwrap bindings are now created once during initialization, not on every call.
• Global Module object pollution. The Emscripten output is now modularized (MODULARIZE=1) and returns a factory function instead of mutating a global.
• formatTime() now returns "N/A" for negative values and wraps correctly at 24 hours.
• init() clears the pending promise on failure, allowing retry on subsequent calls.

Changed

• Source rewritten in TypeScript, compiled by tsup to CJS + ESM with source maps.
• Recompiled WASM with Emscripten using -O3 -flto, SINGLE_FILE, MODULARIZE, NO_FILESYSTEM, and fixed 1MB memory. Output is ~60KB.
• C wrapper (spa_wrapper.c) extended to accept all SPA input parameters and return all output fields.
• Package exports map uses types-first ordering per TypeScript documentation.
• sideEffects: false declared for tree-shaking support.

Removed

• solar-spa.js (old entry point).
• lib/solar-spa.cjs and lib/solar-spa.mjs (replaced by dist/index.cjs and dist/index.mjs).
• index.d.ts (hand-written declarations replaced by generated output in dist/).
• spa.js and spa.wasm (old Emscripten output, replaced by wasm/spa-module.js).
• .npmignore (replaced by the files field in package.json).

1.2.5

• Updated package.json repository field for npm listing.
• Updated README.

1.2.4

• Reverted bug fix from 1.2.1 that introduced a regression.

1.2.3

• Bug fix for onRuntimeInitialized callback timing.

1.2.2

• Rebuilt WASM targeting both web and Node.js environments.
• Removed dependency on fs module.

1.2.1

• Bug fix (reverted in 1.2.4).

1.2.0

• Directly linked WASM file to resolve path resolution bug.

1.1.0

• Added TypeScript declaration file.
• Added explicit WASM file path.

1.0.0

• Initial release. NREL SPA compiled to WebAssembly with a JavaScript wrapper.