From 3acf17d2a726a452cda15acde6631db0e6661e83 Mon Sep 17 00:00:00 2001
From: Andreas Lubbe <git@lubbe.org>
Date: Mon, 8 Jun 2020 11:27:49 +0200
Subject: [PATCH] Support async iteration

---
 README.md            |  8 +++++---
 lib/iterateStream.js | 35 +++++++++++++++++++++++++++++++++++
 unzip.js             |  6 +++++-
 3 files changed, 45 insertions(+), 4 deletions(-)
 create mode 100644 lib/iterateStream.js

diff --git a/README.md b/README.md
index bf376e52..b965e3a8 100644
--- a/README.md
+++ b/README.md
@@ -77,16 +77,18 @@ fs.createReadStream('path/to/archive.zip')
   });
 ```
 
-and the same example using async iterators:
+and the same example using async iterators on node v12 and above:
 
 ```js
 const zip = fs.createReadStream('path/to/archive.zip').pipe(unzipper.Parse({forceStream: true}));
-for await (const entry of zip) {
+for await (const entry of unzipper.iterateStream(zip)) {
   const fileName = entry.path;
   const type = entry.type; // 'Directory' or 'File'
   const size = entry.vars.uncompressedSize; // There is also compressedSize;
   if (fileName === "this IS the file I'm looking for") {
-    entry.pipe(fs.createWriteStream('output/path'));
+    for await (const chunk of unzipper.iterateStream(entry)) {
+      console.log(chunk);
+    }
   } else {
     entry.autodrain();
   }
diff --git a/lib/iterateStream.js b/lib/iterateStream.js
new file mode 100644
index 00000000..331cbe14
--- /dev/null
+++ b/lib/iterateStream.js
@@ -0,0 +1,35 @@
+const {once} = require('events');
+
+module.exports = async function* iterateStream(stream) {
+  const contents = [];
+  stream.on('data', data => contents.push(data));
+
+  let resolveStreamEndedPromise;
+  const streamEndedPromise = new Promise(resolve => (resolveStreamEndedPromise = resolve));
+
+  let ended = false;
+  stream.on('end', () => {
+    ended = true;
+    resolveStreamEndedPromise();
+  });
+
+  let error = false;
+  stream.on('error', err => {
+    error = err;
+    resolveStreamEndedPromise();
+  });
+
+  while (!ended || contents.length > 0) {
+    if (contents.length === 0) {
+      stream.resume();
+      // eslint-disable-next-line no-await-in-loop
+      await Promise.race([once(stream, 'data'), streamEndedPromise]);
+    } else {
+      stream.pause();
+      const data = contents.shift();
+      yield data;
+    }
+    if (error) throw error;
+  }
+  resolveStreamEndedPromise();
+};
diff --git a/unzip.js b/unzip.js
index 07a8d811..fc795b72 100644
--- a/unzip.js
+++ b/unzip.js
@@ -8,4 +8,8 @@ require('setimmediate');
 exports.Parse = require('./lib/parse');
 exports.ParseOne = require('./lib/parseOne');
 exports.Extract = require('./lib/extract');
-exports.Open = require('./lib/Open');
\ No newline at end of file
+exports.Open = require('./lib/Open');
+
+if (parseInt(process.versions.node.split('.')[0], 10) >= 12) {
+  exports.iterateStream = require('./lib/iterateStream');
+}