Previously, these measurements were always performed when the editor
component was mounted. This didn't work in situations where the
component was mounted in a non-visible state. This commit includes a
visibility check in the resize polling we were already doing, kicking
off the measurement process as soon as the editor is visible.
When the cursor is positioned before a character, we always make it the
width of that character. But at the end of a line, there is no character
to use to set the width, so we just use the defaultCharWidth.
This makes the block cursor visible on empty lines in vim-mode.
Previously, SelectionsComponenet::shouldComponentUpdate was storing the
ranges for selections as a side effect. We also were passing boolean
values (cursorMoved and selectionUpdated) to determine if these
components should update.
Now, we compute a simple hash of screen ranges for selections and
cursors in the root component and pass them down. This simplifies
shouldComponentUpdate for selections and allows us to implement one
for cursors.
This fork of React allows data-react-skip-selection-restoration to be
defined on input elements, skipping costly selection restoration that
occurs when the input element is focused during reconciliation.
This commit breaks the initial render of the editor component into two
stages.
The first stage just renders the shell of the editor so the height,
width, line height, and default character width can be measured. Nothing
that depends on these values is rendered on the first render pass.
Once the editor component is mounted, all these values are measured and
we force another update, which fills in the lines, line numbers,
selections, etc.
We also refrain from assigning an explicit height and width on the
model if these values aren't explicitly styled in the DOM, and just
assume the editor will stretch to accommodate its contents.
