diff --git a/lib/constructs/typedef.js b/lib/constructs/typedef.js
new file mode 100644
index 00000000..1488aae9
--- /dev/null
+++ b/lib/constructs/typedef.js
@@ -0,0 +1,40 @@
+"use strict";
+
+const Types = require("../types.js");
+const utils = require("../utils");
+
+module.exports = class Typedef {
+  constructor(idl, opts) {
+    this.idl = idl;
+    this.name = idl.name;
+    this.opts = opts;
+    this.str = "";
+  }
+
+  generate() {
+    this.str += `
+module.exports = {
+  convert(value) {`;
+
+    const conv = Types.generateTypeConversion("value", this.idl.idlType, [], this.opts.customTypes, {
+      handleNullable: true
+    });
+    for (let key in conv.requires) {
+      this.str = `const ${key} = ${conv.requires[key]};\n` + this.str;
+    }
+    this.str += conv.body;
+
+    this.str += `
+    return value;
+  }
+};`;
+
+    return this.str;
+  }
+
+  toString() {
+    this.str = "";
+    this.generate();
+    return this.str;
+  }
+}
diff --git a/lib/transformer.js b/lib/transformer.js
index cfba41d8..375888c4 100644
--- a/lib/transformer.js
+++ b/lib/transformer.js
@@ -8,6 +8,7 @@ const webidl = require("webidl2");
 
 const Interface = require("./constructs/interface");
 const Dictionary = require("./constructs/dictionary");
+const Typedef = require("./constructs/typedef");
 
 class Transformer {
   constructor(opts) {
@@ -77,6 +78,7 @@ class Transformer {
 
     const interfaces = this._interfaces = Object.create(null);
     const dictionaries = this._dictionaries = Object.create(null);
+    const typedefs = this._typedefs = Object.create(null);
     const customTypes = this._customTypes = new Set();
 
     // first we're gathering all full interfaces and ignore partial ones
@@ -107,6 +109,11 @@ class Transformer {
             dictionaries[obj.name] = obj;
             customTypes.add(instruction.name);
             break;
+          case "typedef":
+            obj = new Typedef(instruction, { customTypes });
+            typedefs[obj.name] = obj;
+            customTypes.add(instruction.name);
+            break;
           default:
             if (!this.options.suppressErrors) {
               throw new Error("Can't convert type '" + instruction.type + "'");
@@ -162,12 +169,14 @@ class Transformer {
     yield fs.writeFile(this.options.utilPath, utilsText);
 
     let interfaceStub = yield fs.readFile(__dirname + "/output/interfaceStub.js");
-    let keys = Object.keys(this._interfaces).concat(Object.keys(this._dictionaries));
+    let keys = Object.keys(this._interfaces).concat(Object.keys(this._dictionaries)).concat(Object.keys(this._typedefs));
     for (let key of keys) {
       if (this._interfaces[key]) {
         yield fs.writeFile(path.join(outputDir, this._interfaces[key].name + ".js"), interfaceStub);
-      } else {
+      } else if (this._dictionaries[key]) {
         yield fs.writeFile(path.join(outputDir, this._dictionaries[key].name + ".js"), "");
+      } else {
+        yield fs.writeFile(path.join(outputDir, this._typedefs[key].name + ".js"), "");
       }
     }
 
@@ -196,9 +205,9 @@ const Impl = require("${implFile}.js");\n`;
       yield fs.writeFile(path.join(outputDir, obj.name + ".js"), source);
     }
 
-    keys = Object.keys(this._dictionaries);
+    keys = Object.keys(this._dictionaries).concat(Object.keys(this._typedefs));
     for (let i = 0; i < keys.length; ++i) {
-      const obj = this._dictionaries[keys[i]];
+      const obj = this._dictionaries[keys[i]] || this._typedefs[keys[i]];
       let source = obj.toString();
 
       let relativeUtils = path.relative(outputDir, this.options.utilPath).replace(/\\/g, '/');