Before this commit, the callback passed to `.map()` during attribute
removal was a normal function, not an arrow function. This meant that
the value of `this` in the function body depended on how the callback
was invoked. In this case, the callback was invoked without any
explicit context (it was not called as a method, nor was it called via
`.call()`, `.apply()`, or `.bind()`). Without any explicit context,
the value of `this` depends on strict mode. Currently the function is
in sloppy mode, so `this` refers to the "global this" object (a.k.a.,
`window`). It doesn't make sense for the callback to reference
`window.author`, so I'm assuming the previous behavior was a bug.
Now the function is an arrow function, so the value of `this` comes
from the enclosing lexical context, which in this case is the
AttributeManager object. I believe that was the original intention.
Normally I would let `eslint --fix` do this for me, but there's a bug
that causes:
const x = function ()
{
// ...
};
to become:
const x = ()
=> {
// ...
};
which ESLint thinks is a syntax error. (It probably is; I don't know
enough about the automatic semicolon insertion rules to be confident.)
When comparing original content with the changes made by the user, we
need to ignore some line attribs that are added by content collector,
otherwise we would consider the change started on the first char of the
line -- the '*' that is added when line has line attribs.
In order to be able to handle both #3354 and #3118, we need to take into
account both the styles attribs (to fix#3354) and the line attribs
defined by any of the plugins (to fix#3118), but we can ignore those
extra line attribs that are added by Etherpad and do not add any
functionality (`'lmkr', 'insertorder', 'start'`).
This avoids raising error 'Trying to submit changes as another author in
changeset' when 2 authors change line attributes of the same line. This
fixes issue #2925.
