polyfill fix for Safari stream async iterator

Author: dbushell

deno.json

@@ -1,6 +1,6 @@
 {
   "name": "@dbushell/xml-streamify",
-  "version": "0.7.0",
+  "version": "0.8.0",
   "exports": {
     ".": "./mod.ts",
     "./node": "./src/node.ts",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@dbushell/xml-streamify",
-  "version": "0.7.0",
+  "version": "0.8.0",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/dbushell/xml-streamify.git"

src/parse.ts

@@ -14,6 +14,24 @@ const ignoreTypes: Partial<Record<NodeType, keyof ParseOptions>> = {
   [NodeType.DOCTYPE]: 'ignoreDoctype'
 } as const;
 
+/**
+ * Polyfill for `stream[Symbol.asyncIterator]`
+ */
+async function* asyncIterableStream(
+  stream: ReadableStream<[NodeType, string]>,
+): AsyncGenerator<[NodeType, string], void, unknown> {
+  const reader = stream.getReader();
+  try {
+    while (true) {
+      const { done, value } = await reader.read();
+      if (done) break;
+      yield value;
+    }
+  } finally {
+    reader.releaseLock();
+  }
+}
+
 /**
  * Async generator function for parsing a streamed XML document
  * @param input    URL to fetch and parse (or a ReadableStream)
@@ -51,6 +69,13 @@ export async function* parse(
         signal: options?.signal
       });
 
+    // Apply polyfill if necessary
+    if (typeof stream[Symbol.asyncIterator] !== 'function') {
+      stream[Symbol.asyncIterator] = async function* () {
+        yield* asyncIterableStream(stream);
+      };
+    }
+
     // Set root document as current node
     let node = document;