Compress string using gzip and native browser APIs

Compress string.js

function compress(string, encoding) {
  const byteArray = new TextEncoder().encode(string);
  const cs = new CompressionStream(encoding);
  const writer = cs.writable.getWriter();
  writer.write(byteArray);
  writer.close();
  return new Response(cs.readable).arrayBuffer();
}

function decompress(byteArray, encoding) {
  const cs = new DecompressionStream(encoding);
  const writer = cs.writable.getWriter();
  writer.write(byteArray);
  writer.close();
  return new Response(cs.readable).arrayBuffer().then(function (arrayBuffer) {
    return new TextDecoder().decode(arrayBuffer);
  });
}

@Explosion-Scratch So I've found a way to catch the error message. Apparently it's in the writer's Promise. I still dont know if it is the correct way, but it's one of those moments of "Dont know how or why it works, but it works". If you or anyone else understand more about it, please correct my codes.

async function decomp(str,mode="gzip"){
  // Using Node Buffer for encoder
  str = Buffer.from(str, "base64")
  const cs = new DecompressionStream(mode)
  const writer = cs.writable.getWriter()
  writer.write(str)
  writer.close()
  return await new Response(cs.readable).arrayBuffer()
    .then(
      // Resolve Function
      arr=>(Buffer.from(arr)).toString("utf8"),
      // Reject Function
      async _=>{throw new Error(await Promise.reject(await writer.closed))}
    )
}

let string = [
  // "These strings were compressed!" compressed with gzip and base64 encoder
  `H4sIAAAAAAAACgvJSC1OVSguKcrMSy9WKE8tSlVIzs8tKEotLk5NUQQAfREzrR4AAAA`,
  // Change capital R near the end
  `H4sIAAAAAAAACgvJSC1OVSguKcrMSy9WKE8tSlVIzs8tKEotLk5NUQQAfREzrr4AAAA`,
  // Change 1 char at the end
  `H4sIAAAAAAAACgvJSC1OVSguKcrMSy9WKE8tSlVIzs8tKEotLk5NUQQAfREzrR4AAAx`,
  // Add 1 char at the end
  `H4sIAAAAAAAACgvJSC1OVSguKcrMSy9WKE8tSlVIzs8tKEotLk5NUQQAfREzrR4AAAAx`,
  ],
  result = []

console.clear()

for(let item of string){
  try{
    result.push(
      "Succesfully decompressing!\n\n" + "String Result : "+ (await decomp(item))
    )
  }
  catch(err){
    result.push("Failed to decompress!\n\n"+ err.name +" : "+ err.message)
  }
}

console.log(result.join("\n\n=====================================================================\n\n"))