Convert iterable to array for query parameters

src/v1/internal/packstream-v1.js

@@ -127,6 +127,8 @@ class Packer {
           this.packable(x[i] === undefined ? null : x[i], onError)();
         }
       }
+    } else if (isIterable(x)) {
+      return this.packableIterable(x, onError);
     } else if (x instanceof Structure) {
       var packableFields = [];
       for (var i = 0; i < x.fields.length; i++) {
@@ -160,6 +162,16 @@ class Packer {
     }
   }
 
+  packableIterable(iterable, onError) {
+    try {
+      const array = Array.from(iterable);
+      return this.packable(array, onError);
+    } catch (e) {
+      // handle errors from iterable to array conversion
+      onError(newError(`Cannot pack given iterable, ${e.message}: ${iterable}`));
+    }
+  }
+
   /**
    * Packs a struct
    * @param signature the signature of the struct
@@ -612,6 +624,13 @@ class Unpacker {
   }
 }
 
+function isIterable(obj) {
+  if (obj == null) {
+    return false;
+  }
+  return typeof obj[Symbol.iterator] === 'function';
+}
+
 export {
   Packer,
   Unpacker,

test/v1/session.test.js

@@ -1040,6 +1040,38 @@ describe('session', () => {
     testConnectionTimeout(true, done);
   });
 
+  it('should convert iterable to array', done => {
+    const iterable = {};
+    iterable[Symbol.iterator] = function* () {
+      yield '111';
+      yield '222';
+      yield '333';
+    };
+
+    session.run('RETURN $array', {array: iterable}).then(result => {
+      const records = result.records;
+      expect(records.length).toEqual(1);
+      const received = records[0].get(0);
+      expect(received).toEqual(['111', '222', '333']);
+      done();
+    }).catch(error => {
+      done.fail(error);
+    });
+  });
+
+  it('should fail to convert illegal iterable to array', done => {
+    const iterable = {};
+    iterable[Symbol.iterator] = function () {
+    };
+
+    session.run('RETURN $array', {array: iterable}).then(result => {
+      done.fail('Failre expected but query returned ' + JSON.stringify(result.records[0].get(0)));
+    }).catch(error => {
+      expect(error.message.indexOf('Cannot pack given iterable')).not.toBeLessThan(0);
+      done();
+    });
+  });
+
   function serverIs31OrLater(done) {
     if (serverVersion.compareTo(VERSION_3_1_0) < 0) {
       done();