CODEWITHSUNDEEP
javascriptscala.js
Ford O.
Ford O.

Reputation: 1498

Cannot read property 'Object' of undefined

I am trying to include a generated js module in my webpage. Yet it gives me an error: Uncaught TypeError: Cannot read property 'Object' of undefined at $g["Object"]["freeze"]($env);

The minimal example is:

File index.html:

<html>
  <head>
    <meta content="text/html;charset=utf-8" http-equiv="Content-Type"/>
  </head>
  <body>
    <!-- Note the usage of `type=module` here as this is an ES6 module -->
    <script type="module">

      import { foo } from './foo.js';

      console.log(foo());

    </script>
  </body>
</html>

File foo.js:

'use strict';
/* Scala.js runtime support
 * Copyright 2013 LAMP/EPFL
 * Author: Sébastien Doeraene
 */

/* ---------------------------------- *
 * The top-level Scala.js environment *
 * ---------------------------------- */

// Get the environment info
var $env = (typeof __ScalaJSEnv === "object" && __ScalaJSEnv) ? __ScalaJSEnv : {};

// Global scope
var $g =
  (typeof $env["global"] === "object" && $env["global"])
    ? $env["global"]
    : ((typeof global === "object" && global && global["Object"] === Object) ? global : this);
$env["global"] = $g;


$env["exportsNamespace"] = void 0;


// Freeze the environment info
$g["Object"]["freeze"]($env);

export function foo() { return "Hello"; }

But if I just copy paste the script into chrome console, then everything works as it should.

Upvotes: 0

Views: 454

Answers (1)

sjrd
sjrd

Reputation: 22085

You are hitting a bug in Scala.js 0.6.x: https://github.com/scala-js/scala-js/issues/3677. The global detection code in var $g = ... is incorrect when used in ES modules outside of Node.js (e.g., in a browser) and fails to discover the correct global object.

The issue mentions a workaround: add the following <script> tag in your HTML file (before the one that imports the Scala.js code):

<script type="text/javascript">
var __ScalaJSEnv = { global: window };
</script>

This will explicitly tell Scala.js what the global object is, i.e., window.

The issue is fixed in Scala.js 1.x, whose RC1 was released two days ago.

Upvotes: 1

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