Merge pull request #3765 from Mischanix/js-typed-arrays

Javascript helper to get typed array views

src/idl_gen_js.cpp

@@ -509,12 +509,24 @@ static void GenStruct(const Parser &parser, StructDef &struct_def,
     }
     code += "};\n\n";
 
-    // Emit a length helper
+    // Emit vector helpers
     if (field.value.type.base_type == BASE_TYPE_VECTOR) {
+      // Emit a length helper
       GenDocComment(code_ptr, "@returns {number}");
       code += object_name + ".prototype." + MakeCamel(field.name, false);
       code += "Length = function() {\n" + offset_prefix;
       code += "this.bb.__vector_len(this.bb_pos + offset) : 0;\n};\n\n";
+
+      // For scalar types, emit a typed array helper
+      auto vectorType = field.value.type.VectorType();
+      if (IsScalar(vectorType.base_type)) {
+        GenDocComment(code_ptr, "@returns {" + GenType(vectorType) + "Array}");
+        code += object_name + ".prototype." + MakeCamel(field.name, false);
+        code += "Array = function() {\n" + offset_prefix;
+        code += "new " + GenType(vectorType) + "Array(this.bb.bytes().buffer, "
+          "this.bb.__vector(this.bb_pos + offset), "
+          "this.bb.__vector_len(this.bb_pos + offset)) : null;\n};\n\n";
+      }
     }
   }
 

tests/JavaScriptTest.js

@@ -106,6 +106,13 @@ function testBuffer(bb) {
   }
   assert.strictEqual(invsum, 10);
 
+  var invsum2 = 0;
+  var invArr = monster.inventoryArray();
+  for (var i = 0; i < invArr.length; i++) {
+    invsum2 += invArr[i];
+  }
+  assert.strictEqual(invsum2, 10);
+
   var test_0 = monster.test4(0);
   var test_1 = monster.test4(1);
   assert.strictEqual(monster.test4Length(), 2);
@@ -169,7 +176,7 @@ function testUnicode() {
   var json = JSON.parse(fs.readFileSync('unicode_test.json', 'utf8'));
 
   // Test reading
-  var bb = new flatbuffers.ByteBuffer(new Uint8Array(correct));
+  function testReadingUnicode(bb) {
     var monster = MyGame.Example.Monster.getRootAsMonster(bb);
     assert.strictEqual(monster.name(), json.name);
     assert.deepEqual(new Buffer(monster.name(flatbuffers.Encoding.UTF8_BYTES)), new Buffer(json.name));
@@ -184,6 +191,8 @@ function testUnicode() {
       assert.strictEqual(monster.testarrayofstring(i), string);
       assert.deepEqual(new Buffer(monster.testarrayofstring(i, flatbuffers.Encoding.UTF8_BYTES)), new Buffer(string));
     });
+  }
+  testReadingUnicode(new flatbuffers.ByteBuffer(new Uint8Array(correct)));
 
   // Test writing
   var fbb = new flatbuffers.Builder();
@@ -203,7 +212,7 @@ function testUnicode() {
   MyGame.Example.Monster.addTestarrayoftables(fbb, testarrayoftablesOffset);
   MyGame.Example.Monster.addName(fbb, name);
   MyGame.Example.Monster.finishMonsterBuffer(fbb, MyGame.Example.Monster.endMonster(fbb));
-  assert.deepEqual(new Buffer(fbb.asUint8Array()), correct);
+  testReadingUnicode(new flatbuffers.ByteBuffer(fbb.asUint8Array()));
 }
 
 var __imul = Math.imul ? Math.imul : function(a, b) {

tests/monster_test_generated.js

@@ -447,6 +447,14 @@ MyGame.Example.Monster.prototype.inventoryLength = function() {
   return offset ? this.bb.__vector_len(this.bb_pos + offset) : 0;
 };
 
+/**
+ * @returns {Uint8Array}
+ */
+MyGame.Example.Monster.prototype.inventoryArray = function() {
+  var offset = this.bb.__offset(this.bb_pos, 14);
+  return offset ? new Uint8Array(this.bb.bytes().buffer, this.bb.__vector(this.bb_pos + offset), this.bb.__vector_len(this.bb_pos + offset)) : null;
+};
+
 /**
  * @returns {MyGame.Example.Color}
  */
@@ -555,6 +563,14 @@ MyGame.Example.Monster.prototype.testnestedflatbufferLength = function() {
   return offset ? this.bb.__vector_len(this.bb_pos + offset) : 0;
 };
 
+/**
+ * @returns {Uint8Array}
+ */
+MyGame.Example.Monster.prototype.testnestedflatbufferArray = function() {
+  var offset = this.bb.__offset(this.bb_pos, 30);
+  return offset ? new Uint8Array(this.bb.bytes().buffer, this.bb.__vector(this.bb_pos + offset), this.bb.__vector_len(this.bb_pos + offset)) : null;
+};
+
 /**
  * @param {MyGame.Example.Stat=} obj
  * @returns {MyGame.Example.Stat}
@@ -653,6 +669,14 @@ MyGame.Example.Monster.prototype.testarrayofboolsLength = function() {
   return offset ? this.bb.__vector_len(this.bb_pos + offset) : 0;
 };
 
+/**
+ * @returns {Int8Array}
+ */
+MyGame.Example.Monster.prototype.testarrayofboolsArray = function() {
+  var offset = this.bb.__offset(this.bb_pos, 52);
+  return offset ? new Int8Array(this.bb.bytes().buffer, this.bb.__vector(this.bb_pos + offset), this.bb.__vector_len(this.bb_pos + offset)) : null;
+};
+
 /**
  * @param {flatbuffers.Builder} builder
  */