control-has-associated-label accepts whitespace as a label

[wobo-nate]

The problem

The control-has-associated-label rule currently accepts whitespace as an accessible label. This issue is exaggerated by the use of prettier which may introduce line breaks and other whitespace automatically, defeating the rule.

Examples

All of the below examples lack accessible labels.

<button></button>                <!-- rule correctly flags invalid markup -->
<button> </button>               <!-- rule fails to flag invalid markup -->

<button aria-label=""></button>  <!-- rule correctly flags invalid markup -->
<button aria-label=" "></button> <!-- rule fails to flag invalid markup -->

Suggested fix

Update mayHaveAccessibleLabel to .trim() the node's value before asserting truthiness.

[ljharb]

Seems a reasonable bugfix; anyone relying on it shouldn't be :-)