Error: Failed to instantiate module restangular due to: '_' is undefined

Question

When first using Restangular on a working website I got the following JavaScript error:

Failed to instantiate module restangular due to: '_' is undefined

What am I missing? What does it mean that '_' is undefined (in the Restangular module)?

Answer 1

It's a simple oversight. The '_' (underscore) is a JavaScript utility library that Restangular uses and depends on. Include Lodash or Undrescore library before the AngularJS library (in your HTML):

<script src="lodash.js"></script>

or

<script src="underscore.js"></script>

PS: Double check the library script and path exist as referenced in your SCRIPT tag.

Additional readings:

• Restangular Dependencies
• Why Does Restangular Depend on lodash / underscore
• Differences between lodash and underscore