angular cannot read property '1' of null is not a useful error message.

[steowens]

What does this error even mean. Error message is not actionable.

[lgalfaso]

can you create a plunker tat shows the error? without this there is not a lot that can be done

[caitp]

betting this is coming from https://github.com/angular/angular.js/blob/master/src/ng/parse.js#L920

[steowens]

I think it was caused by the following syntax error on a div tag
`

[caitp]

angular isn't the one parsing the DOM, that's your web browser.

[steowens]

Why is the error message generated in the angular call stack?

[steowens]

TypeError: Cannot read property '1' of null
at angular.js:8411
at angular.js:7592
at forEach (angular.js:331)
at nodeLinkFn (angular.js:7579)
at compositeLinkFn (angular.js:7075)
at nodeLinkFn (angular.js:7717)
at angular.js:7953
at processQueue (angular.js:13171)
at angular.js:13187
at Scope.$get.Scope.$eval (angular.js:14384)

[caitp]

Betting on this https://github.com/angular/bower-angular/blob/ecf0435da949836c63ebf048ea8b7710542e33ce/angular.js#L8414-L8416 --- however there's still no way we'd be able to be like "hey your html is screwed up on this line and this column", that's not feasible

[steowens]

The relevant materials to repro are as follows add the following to index.html

`

`

Add the following to the top level module:
.directive('signupForm', function(){ return { restrict: 'A', templateUrl: '/static/templates/signup-section.html' } })

Add the following to signup-section.html

<div class="content" data-section-content ng-controller="SignupFormController as signupFormCtrl>
</div>

[caitp]

it's pretty clear what the problem is, but we still can't really say where the error happened in your code, we have no way of knowing. best we can do is say "hey, you screwed up your controller name somewhere"

[steowens]

Here is the code where the exception gets thrown:

if (isString(expression)) { match = expression.match(CNTRL_REG), constructor = match[1], identifier = identifier || match[3]; expression = controllers.hasOwnProperty(constructor)

It fails on constructor=match[1] You are not testing for a proper match here by the way and you are tossing an error way up the stack.

The input to the function contains the following value in expression:

"SignupFormController as signupFormCtrl>
    <div class="

So rather than punting the exception up the stack if you were to do something about catching the exeption in match, then wrapping it with contextual information provided by the value of expression you could make the error a thousand times more informative.