Why Does ExecJS::RuntimeError Keep Appearing on Windows While Following the Rails Tutorial?

ExecJS::RuntimeError on Windows Troubling Rails Tutorial Users

Issue:
When following the Ruby on Rails tutorial on a Windows machine, users encounter a persistent "ExecJS::RuntimeError" when trying to include the "sessions.js.coffee" file in their application. This error prevents the tutorial from progressing.

Investigation:
Despite numerous attempts to resolve the issue, including suggestions to remove specific lines of code or install Node.js, the root cause remained elusive. The error message indicated a problem with running JavaScript code in the browser.

Underlying Cause:
After extensive research, it was discovered that the JavaScript runtime on Windows was not functioning correctly with ExecJS, the Ruby library responsible for executing JavaScript from within Ruby code. Although ExecJS supports the Windows Script Host (JScript), it was encountering issues due to a specific configuration in the ExecJS runtime configuration file.

Resolution:
To fix the issue, users needed to modify the "runtimes.rb" file in ExecJS and make three specific changes:

1. Remove the " //U" flag from the JScript command line argument.
2. Change the encoding to "UTF-8" from "UTF-16LE".
3. Restart the Rails server.

Implications:

1. Ignoring the Issue: Removing the "= require_tree" line only bypassed the problem and did not provide a genuine solution.
2. Installing Node.js: While installing Node.js could circumvent the issue, it introduced additional software that was not necessary for solving the underlying problem.
3. Fixing the Issue: Modifying the "runtimes.rb" file addressed the root cause of the issue and ensured that ExecJS could properly run JavaScript code using the built-in JavaScript runtime on Windows.

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