wasm_lzma 0.1.0

esm modules for lzma/lzma2 compression and/or decompression, with sync and async (worker) versions
Documentation 
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Compress LZMA best compression</title>
<style>
*{margin:0;padding:0;box-sizing:border-box}
html{height:100%;font:4vmin monospace;background:#222;color:#eee}
body{min-height:100%;padding:1rem;display:grid;place-items:center}
main{text-align:center}
body.dragover::before{
  content:'';
  position:absolute;
  inset:1rem;
  background:rgba(200, 200, 200, .1);
  border:2px solid rgba(200, 200, 200, .25);
}
main a{color:#adf}
main:not(:empty){font-size:67%}
main.ready:not(.busy):empty::before{
  content:'Drag a file here';
  font-style:italic;
  opacity:.5;
}
main.busy::before{
  content:'';
  display:inline-block;
  width:2rem;height:2rem;
  border-radius:50%;
  border:.1rem solid rgba(200, 200, 200, .5);
  border-top-color:rgb(200, 200, 200);
  animation:spin 1s ease-in-out infinite;
  will-change:transform;
}
@keyframes spin{
  to{transform:rotate(360deg)}
}
</style>
</head>
<body>
<main></main>
</body>
<script type="module">
import lzma from './lzma_enc_worker.mjs';
import unlzma from './lzma_dec_worker.mjs';
// import {lzma,unlzma} from './lzma.mjs';

const main=document.querySelector('main');
main.classList.add('ready');
['dragenter','dragover','dragleave','drop'].forEach(it=>{
  window.addEventListener(it,e=>{
    e.preventDefault();
    e.stopPropagation();
    document.body.classList.remove('dragover');
  },false);
});
const dragListener=e=>{
  e.dataTransfer.dropEffect='copy';
  document.body.classList.add('dragover');
};
window.addEventListener('dragover',dragListener,false);
const read=file=>new Promise(r=>{
  const reader=new FileReader();
  reader.onloadend=()=>r(new Uint8Array(reader.result));
  reader.readAsArrayBuffer(file);
});
const dropListener=async e=>{
  main.textContent='';
  main.classList.add('busy');
  window.removeEventListener('dragover',dragListener);
  window.removeEventListener('drop',dropListener);
  const file=e.dataTransfer.files.item(0);
  console.log(file.size);
  const uncompressed=await read(file);
  const hash=new Uint8Array(await crypto.subtle.digest('SHA-256',uncompressed));
  const compressed=await lzma(uncompressed,9);
  const decompressed=await unlzma(compressed);
  new Uint8Array(await crypto.subtle.digest('SHA-256',decompressed)).forEach((it,i)=>{
    if(it!==hash[i]) throw new Error('Verification failed.');
  });
  const blob=new Blob([compressed],{type: 'octet/stream'});
  const url=await new Promise((resolve,reject)=>{
    const reader=new FileReader();
    reader.addEventListener('load',e=>resolve(e.target.result));
    reader.addEventListener('error',reject);
    reader.readAsDataURL(blob);
  });
  const a=document.createElement('a');
  a.href=url;
  a.download=`${file.name}.lzma`;
  a.innerHTML=`${file.name}.lzma`;
  main.classList.remove('busy');
  main.appendChild(a);
  main.innerHTML+=`<br>(${compressed.byteLength} B)`;
  window.addEventListener('dragover',dragListener,false);
  window.addEventListener('drop',dropListener,false);
};
window.addEventListener('drop',dropListener,false);
</script>
</html>