Uncaught TypeError: angular.lowercase is not a function

Angular 1.7.* still has lowercase function but it's renamed to $$lowercase. This is a possible workaround. Buyer beware based on Angular documentation.

angular.module('MyApp').config(function() {
  angular.lowercase = angular.$$lowercase;  
});

Ovidiu Dolha's answer got me almost there. If you look at the pre-deprecation implementation of the lowercase function, it is a bit more. This shim implementation did the trick for me:

/**
 * @brief Shim for textAngular in order to make it compatible with the latest 
 *   version of angularjs
 */

function lowercase(string) {
  return (typeof string === 'string') ? string.toLowerCase() : string;
}

// Angular deprecated the lowercase function as of v1.6.7. TextAngular hasn't 
// updated to reflect this
angular.lowercase = lowercase;

I would like to share my views so that it will help other people who are struggling like me, the main problem is angularJS officially removed lowercase and uppercase functions from their library so people who are using textAngular-sanitize.js will get this error because textangular still has this method in its library which will through this issue.

You can either remove textAngular-sanitize.js from your project or you can include Ovidiu Dolha code in you app.js before angular.module loads as below.

angular.uppercase=function(text){
 return text.toUpperCase();
 }
 angular.lowercase=function(text){
 return text.toLowerCase();
 }

angular.module('sampleApp', ....)

The code given by Ovidiu Dolha

angular.lowercase = text => text.toLowerCase();

Can be written as

angular.lowercase=function(text){
     return text.toLowerCase();
     }

Both will work. Thank you.

As you can see here, angular deprecated their lowercase util method.

The library you use has not updated yet and is therefore only compatible with an angular version before 1.6.7. But since you get this error, the angular version you use is probably higher.

You can either

(A) Downgrade angular to 1.6.7, in your bower.json:

"dependencies": {
   "angular": "1.6.7",
   ...
}
"resolutions": {
   "angular": "1.6.7"
}

(B) Create a simple workaround by adding these methods back as such:

angular.lowercase = text => text.toLowerCase();

Make sure this is done after angular is loaded but before your app starts.