trimContent.js

import { EditorState, Modifier, SelectionState } from 'draft-js';

/**
 * Will remove the last block in the editor if it's empty.
 *
 * @param  {EditorState} editorState
 * @return {EditorState}
 */
export default function trimContent(editorState) {
    const content = editorState.getCurrentContent();
    const lastBlock = content.getBlockMap().last();

    if (lastBlock.getType() === 'unstyled' && lastBlock.getText().trim() === '') {
        const blockBefore = content.getBlockBefore(lastBlock.getKey());
        const targetRange = new SelectionState({
            anchorKey: blockBefore.getKey(),
            anchorOffset: blockBefore.getLength(),
            focusKey: lastBlock.getKey(),
            focusOffset: lastBlock.getLength(),
        });

        const withoutLastBlock = Modifier.removeRange(content, targetRange, 'backward');
        return EditorState.push(editorState, withoutLastBlock, 'remove-range');
    }

    return editorState;
}