Slate: Chinese IME throws out errors

[winfield]

I want to report a bug?

What's the current behavior?

Using Chinese IME on slatejs.org throws out errors

````
Error: Failed to execute 'removeChild' on 'Node': The node to be removed is not a child of this node.
at removeChild (http://slatejs.org/build.prod.js:4828:7974)
at a (http://slatejs.org/build.prod.js:4825:25233)
at commitDeletion (http://slatejs.org/build.prod.js:4825:26981)
at n (http://slatejs.org/build.prod.js:4825:31488)
at u (http://slatejs.org/build.prod.js:4826:1356)
at c (http://slatejs.org/build.prod.js:4826:1793)
at batchedUpdates (http://slatejs.org/build.prod.js:4826:4655)
at qb (http://slatejs.org/build.prod.js:4825:3879)
at ob (http://slatejs.org/build.prod.js:4825:3813)
at Object.batchedUpdates (http://slatejs.org/build.prod.js:4826:19682)
`````

TypeError: Cannot read property 'node' of null at t.n.updateSelection (http://slatejs.org/build.prod.js:5014:4115) at t.n.componentDidUpdate (http://slatejs.org/build.prod.js:5014:3374) at commitLifeCycles (http://slatejs.org/build.prod.js:4825:27709) at n (http://slatejs.org/build.prod.js:4825:31692) at u (http://slatejs.org/build.prod.js:4826:1356) at c (http://slatejs.org/build.prod.js:4826:1793) at batchedUpdates (http://slatejs.org/build.prod.js:4826:4655) at qb (http://slatejs.org/build.prod.js:4825:3879) at ob (http://slatejs.org/build.prod.js:4825:3813) at Object.batchedUpdates (http://slatejs.org/build.prod.js:4826:19682)

OS: macOS High Sierra
Browser: Chrome version 61
Slate version: slatejs.org

[doodlewind]

This error is only triggered by macOS native pinyin IME, third party pinyin IME (Sougou, Baidu, etc.) does not throw this error, instead they 'eat' characters afterwards.

[winfield]

not just the pinyin IME, all the native Chinese IMEs have the issue.

[J22Melody]

IMEs don't eat characters afterwards anymore, but I can still reproduce the error if I try to type Chinese in an empty new line, like the first gif shows.

OS: macOS High Sierra
Browser: Chrome version 61
Slate version: slatejs.org
Input Method: Pinyin - Simplified / Sougou Pinyin

[chemzqm]

The error is caused by the <br> added by slate https://github.com/ianstormtaylor/slate/blob/master/packages/slate-react/src/components/leaf.js#L130

It looks like some browser would remove <br> after IME complete, so react could not find it and throw error. One solution is use a whitespace instead:

    if (text == '' && parent.kind == 'block' && parent.text == '') return '\u2060'

[zhengjunxin]

@chemzqm Is add that code in the renderText method like this?

However, it still crash after inputting Chinese