fix: [1706] Handle non string values gracefully for removeAttribute o…

[OlaviSau]

…n elements

[capricorn86]

Nice contribution!

[capricorn86]

The attribute is actually not ignored when name is not a string, it is stringified.

You can test it with this:

var div = document.createElement('div');

div.setAttribute(null, 'test');

// Outputs '<div null="test"></div>'
console.log(div.outerHTML);

div.removeAttribute(null);

// Outputs '<div></div>'
console.log(div.outerHTML);

I think it is best if we add the stringify using String() to NamedNodeMap to methods such as getNamedItem().

[OlaviSau]

One note - there is no need to implement a check on NamedNodeMap setNamedItem because Attr constructor should not available in the first place, thus an invalid name should not be able to be created unless the user explicitly goes out of their way to do so.

[OlaviSau]

This is quite a significant breaking change even though it's more correct this way. Perhaps we should add a strict mode flag and not enable it by default and have a transition period?