Undo / Redo does not work properly for EmbedBlot.

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Steps for Reproduction

1. Added a new EmbedBlot and defined value functions.
2. After I add a new EmbedBlot on the Quill component, I try CTRL+Z for undo.

• When there is no appended texts, undo just removes that Custom Blot perfect. But if I try redo, then it just adds a simple text(from value() function) and does not add CustomBlot back.
• When there is appended texts, its behavior is really messy. I am gonna attach the video below for that.

class MathInputCmp extends Embed {
  state = {
    mathField: null
  };

  static create(val) {
    const node = super.create();
    node.innerHTML = '<span class="input__math__field"></span>';
    node.setAttribute('data-latex', val);
    node.setAttribute('contenteditable', false);
    return node;
  }

  static value(domNode) {
    return domNode.getAttribute('data-latex');
  }

  static formats(domNode) {
    const MQ = window.MathQuill.getInterface(2);
    const mathField = MQ.StaticMath(domNode.firstChild);
    return {
      "data-latex": mathField.latex()
    };
  }

  constructor(domNode, value) {
    super(domNode, value);
    const MQ = window.MathQuill.getInterface(2);
    const mathField = MQ.StaticMath(domNode.firstChild);
    mathField.latex(value);
    domNode.setAttribute('data-latex', value);
    this.state = {
      mathField
    };
  }

  value() {
    return this.state.mathField.latex();
  }

  format(name, value) {
    if (name === 'data-latex') {
      if (value) {
        this.domNode.setAttribute('data-latex', value);
      } else {
        this.domNode.removeAttribute('data-latex');
      }
    } else {
      super.format(name, value);
    }
  }
}
MathInputCmp.blotName = "MathInput";
MathInputCmp.tagName = "span";
MathInputCmp.className = "input__math";
Quill.register(MathInputCmp, true);

https://vimeo.com/319684211

Expected behavior:

1. undo should remove CustomBlot completely.
2. redo should restore CustomBlot again.

Actual behavior:

1. undo does not remove CustomBlot sometimes.
2. redo is not adding CustomBlot back never.

Platforms:

Google Chrome 72.0 Using this on react react-quill: 1.3.3 quilljs: 1.2.6

Version:

quilljs: 1.2.6

[fritzfr]

Similar problem. For me though, undo restores the custom blot with the word true, no matter what was in there before.

I am on 2.0.0-dev.3.

[Chris-Kin]

I also encounter this problem. We need get a complete delta information when excute ‘undo’ operation. Or whole node is also accepted.