test naive polyfill for webstream deflate-raw

needed until nodejs/node#50097 is released

test/deflate-raw.js

@@ -0,0 +1,31 @@
+if (check()) {
+  polyfill();
+}
+
+/* global DecompressionStream */
+function check() {
+  try {
+    new DecompressionStream('deflate-raw');
+    return false;
+  } catch {
+    // polyfill needed
+    return true;
+  }
+}
+
+function polyfill() {
+  const { createInflateRaw } = require('node:zlib');
+  const { Duplex } = require('node:stream');
+
+  class PolyfilledStream extends DecompressionStream {
+    constructor(format) {
+      if (format === 'deflate-raw') {
+        return Duplex.toWeb(createInflateRaw());
+      }
+      super(format);
+    }
+  }
+
+  globalThis.DecompressionStream = PolyfilledStream;
+
+}

test/import.js

@@ -4,6 +4,8 @@ const assert = require('node:assert/strict');
 const fs = require('node:fs');
 const path = require('node:path');
 
+require('./deflate-raw');
+
 const parse = require('..');
 
 function openAsBlob(name) {
@@ -18,6 +20,13 @@ test('should parse kmz', async function () {
   assert.deepEqual(trip, expected);
 });
 
+test('should parse deflated kmz', async function () {
+  const blob = await openAsBlob('/fixtures/usa.deflated.kmz');
+  const trip = await parse(blob);
+  const expected = require('./fixtures/usa.json');
+  assert.deepEqual(trip, expected);
+});
+
 test('should raise error on a file that contains invalid KML', async function () {
   const stream = await openAsBlob('/fixtures/invalid-kml-inside.kmz');
   await assert.rejects(parse(stream), /Unclosed tag/i);