trim className before split to avoid empty className

[1inus]

in function patchAttributes(dom, prev, cur), className like 'someClassName ' get an array contains empty element after split(' ') called. dom.classList.add(emptyString) will case an exception : Uncaught (in promise) DOMException: Failed to execute 'add' on 'DOMTokenList': The token provided must not be empty.

[marijnh]

We're targeting platforms (specically IE11) that don't have trim. Maybe express this as a filter call after the split instead to avoid that?

[BrianHung]

MDN and caniuse says that String.prototype.trim has been supported since IE10.

Using .split(" ").filter(Boolean) is more compatible (with up to IE9) but prosemirror homepage says compatibility starts at IE11.

Edit: I initially made a PR (#89) to add trim() to both prevClass and curClass, but I realized another benefit of using a boolean filter is that it removes all trailing, leading, and inner white space while trim only removes trailing and leading.

[marijnh]

Ah, I guess it's trimStart/trimEnd that aren't in IE11. Thanks for pointing that out. I agree the filter patch is nicer.