# Developer notes

The [Makefile](./Makefile) is written for a linux environment.

To build libhdf5, you must have [Emscripten](https://emscripten.org/docs/getting_started/downloads.html) installed and activated, so that the ```emcmake``` and ```emmake``` and ```emcc``` commands are available.

Then just type 
```
make
```

libhdf5.a and libhdf5_hl.a are retrieved by CMake from the [libhdf5-wasm](https://github.com/usnistgov/libhdf5-wasm) repository.

and are used to compile ```./src/hdf5_util.cc``` to ```./dist/esm/hdf5_util.js``` (the WASM is embedded in that file, in SINGLE_FILE mode)

which are then used by ```./dist/esm/hdf5_hl.js``` (ESM)

(and also ```./dist/node/hdf5_util.js``` which is used by ```./dist/node/hdf5_hl.js```, the nodejs entry point)

an additional build ```./dist/iife/h5wasm.js``` is created from the ESM browser build, as an [IIFE](https://developer.mozilla.org/en-US/docs/Glossary/IIFE) which can be directly used in a Firefox web worker, with `importScripts()`.  The exported names are exposed under the global name `h5wasm` after import.

## distributable files
The main library entrypoints are generated from ```./src/hdf5_hl.ts``` with the Typescript compiler by running ```npm run build```.  This also generates the Typescript typings file ```./src/hdf5_hl.d.ts```