javascript - Slate.js throws an error when inserting a new node at selected region

Question

Relevant code blocks:

        <Slate editor={editor} value={value} onChange={value => {
            setValue(value);

            const { selection } = editor;
            // if nothing is currently selected under the cursor
            if (selection && Range.isCollapsed(selection)) {
                const [start] = Range.edges(selection);
                // if the two characters beforce the cursor are {{, select them and replace with a template block
                const before = Editor.before(editor, start, {distance: 2})
                const beforeRange = before && Editor.range(editor, before, start)
                const beforeText = beforeRange && Editor.string(editor, beforeRange)
                const beforeMatch = beforeText && beforeText.match(/{{/);
                if (beforeMatch) {
                    Transforms.select(editor, beforeRange as Location);
                    insertTemplateBlock(editor, {name: "test"})
                }
            }
        }}>
...
</Slate>

export const insertTemplateBlock = (editor: Editor, {name, opts, defaultValue}: TemplateBlockProps) => {
    const templateBlock = { type: "template-block", name, opts, defaultValue, children: [{text: ''}] }
    Transforms.insertNodes(editor, templateBlock);
    Transforms.move(editor);
}

Specifically, it always breaks at the 2nd line within the insertTemplateBlock function, giving an error along the lines of:

Cannot find a descendant at path [0,2] in node: {"children":[{"type":"paragraph","children":[{"text":"Thing is working {{"}]}],"operations":[{"type":"insert_text","path":[0,0],"offset":18,"text":"{"},{"type":"set_selection","properties":{"anchor":{"path":[0,0],"offset":19}},"newProperties":{"anchor":{"path":[0,0],"offset":17}}},{"type":"remove_text","path":[0,0],"offset":17,"text":"{{"},{"type":"insert_node","path":[0,1],"node":{"type":"template-block","name":"test","children":[{"text":""}]}},{"type":"set_selection","properties":{"anchor":{"path":[0,0],"offset":17},"focus":{"path":[0,0],"offset":17}},"newProperties":{"anchor":{"path":[0,1,0],"offset":0},"focus":{"path":[0,1,0],"offset":0}}},{"type":"insert_node","path":[0,2],"node":{"text":""}},{"type":"set_selection","properties":{"anchor":{"path":[0,1,0],"offset":0},"focus":{"path":[0,1,0],"offset":0}},"newProperties":{"anchor":{"path":[0,2],"offset":0},"focus":{"path":[0,2],"offset":0}}}],"selection":{"anchor":{"path":[0,2],"offset":0},"focus":{"path":[0,2],"offset":0}},"marks":null,"history":{"undos":[[{"type":"set_selection","properties":null,"newProperties":{"anchor":{"path":[0,0],"offset":0},"focus":{"path":[0,0],"offset":0}}}],[{"type":"insert_text","path":[0,0],"offset":0,"text":"T"},{"type":"insert_text","path":[0,0],"offset":1,"text":"h"},{"type":"insert_text","path":[0,0],"offset":2,"text":"i"},{"type":"insert_text","path":[0,0],"offset":3,"text":"n"},{"type":"insert_text","path":[0,0],"offset":4,"text":"g"},{"type":"insert_text","path":[0,0],"offset":5,"text":" "},{"type":"insert_text","path":[0,0],"offset":6,"text":"i"},{"type":"insert_text","path":[0,0],"offset":7,"text":"s"},{"type":"insert_text","path":[0,0],"offset":8,"text":" "},{"type":"insert_text","path":[0,0],"offset":9,"text":"w"},{"type":"insert_text","path":[0,0],"offset":10,"text":"o"},{"type":"insert_text","path":[0,0],"offset":11,"text":"r"},{"type":"insert_text","path":[0,0],"offset":12,"text":"k"},{"type":"insert_text","path":[0,0],"offset":13,"text":"i"},{"type":"insert_text","path":[0,0],"offset":14,"text":"n"},{"type":"insert_text","path":[0,0],"offset":15,"text":"g"},{"type":"insert_text","path":[0,0],"offset":16,"text":" "},{"type":"set_selection","properties":null,"newProperties":{"anchor":{"path":[0,0],"offset":17},"focus":{"path":[0,0],"offset":17}}}],[{"type":"insert_text","path":[0,0],"offset":17,"text":"{"},{"type":"insert_text","path":[0,0],"offset":18,"text":"{"},{"type":"set_selection","properties":{"anchor":{"path":[0,0],"offset":19}},"newProperties":{"anchor":{"path":[0,0],"offset":17}}},{"type":"remove_text","path":[0,0],"offset":17,"text":"{{"},{"type":"insert_node","path":[0,1],"node":{"type":"template-block","name":"test","children":[{"text":""}]}},{"type":"set_selection","properties":{"anchor":{"path":[0,0],"offset":17},"focus":{"path":[0,0],"offset":17}},"newProperties":{"anchor":{"path":[0,1,0],"offset":0},"focus":{"path":[0,1,0],"offset":0}}},{"type":"insert_node","path":[0,2],"node":{"text":""}},{"type":"set_selection","properties":{"anchor":{"path":[0,1,0],"offset":0},"focus":{"path":[0,1,0],"offset":0}},"newProperties":{"anchor":{"path":[0,2],"offset":0},"focus":{"path":[0,2],"offset":0}}}]],"redos":[]}}

This does not happen in their mentions example, which uses a similar logic. Any help would be appreciated!

Codesandbox: https://codesandbox.io/s/elastic-turing-dv9bm?file=/src/App.tsx

UPDATE: I have since found out that this problem can be avoided by moving the insertion logic (currently in the if statement) to a useEffect hook depending on a target value containing the selection, similar to how Slate's mentions example works. However, I am still curious to know why Slate breaks in the way that it does when I write it in the way of the question statement.

question from:https://stackoverflow.com/questions/65852411/slate-js-throws-an-error-when-inserting-a-new-node-at-selected-region

Answer 1

I think your issue stems from the fact that <Slate> is the context provider, and you should actually be using a nested <Editable> component to handle events - in your case onKeyDown. In the specific example you mentioned, I believe you are encountering a race condition which won't occur with the nested Editable component. See Installing Slate under Walkthroughs in the documentation.

https://docs.slatejs.org/walkthroughs/01-installing-slate