ianstormtaylor/slate · critical · Error

[Slate] editor is invalid! You passed: ${Scrubber.stringify(

Error message

[Slate] editor is invalid! You passed: ${Scrubber.stringify(editor)}

What it means

The <Slate> component validates that the editor prop is a real Slate Editor instance (Editor.isEditor). Passing a plain object, a factory's un-configured return, or something with a different shape fails this check and throws on mount before any rendering.

Source

Thrown at packages/slate-react/src/components/slate.tsx:48

    onChange,
    onSelectionChange,
    onValueChange,
    initialValue,
    ...rest
  } = props

  // Run once on first mount, but before `useEffect` or render
  React.useState(() => {
    if (!Node.isNodeList(initialValue)) {
      throw new Error(
        `[Slate] initialValue is invalid! Expected a list of elements but got: ${Scrubber.stringify(
          initialValue
        )}`
      )
    }

    if (!Editor.isEditor(editor)) {
      throw new Error(
        `[Slate] editor is invalid! You passed: ${Scrubber.stringify(editor)}`
      )
    }

    editor.children = initialValue
    Object.assign(editor, rest)
  })

  const { selectorContext, onChange: handleSelectorChange } =
    useSelectorContext()

  const onContextChange = useCallback(() => {
    if (onChange) {
      onChange(editor.children)
    }
    if (
      onSelectionChange &&
      editor.operations.find(op => op.type === 'set_selection')

View on GitHub (pinned to 72a37c701e)

Solutions

1. Create the editor with withReact(createEditor()) from the same slate-react/slate versions and pass that instance directly
2. Deduplicate slate in node_modules (add an npm resolution/yarn nohoist) so only one copy exists
3. Verify package versions of slate and slate-react match (no cross-major mix)

Example fix

// before
<Slate editor={editorFromState} initialValue={value}> // plain object

// after
const editor = useMemo(() => withReact(createEditor()), [])
<Slate editor={editor} initialValue={value}>

if (!Editor.isEditor(editor)) {
  throw new Error('Pass a withReact(createEditor()) instance to <Slate>')
}

const isSlateEditor = (e: unknown): e is Editor => Editor.isEditor(e)

When it happens

Trigger: <Slate editor={{}} ...>; passing createEditor result from a different slate version/instance; passing a React state value, a ref, or an editor-like object missing required properties (isEditor marker, operations, etc.).

Common situations: Multiple copies of the slate package in node_modules (npm/yarn hoisting issues) so instanceof-style checks fail; passing window.editor set incorrectly; HMR or SSR setups replacing modules; upgrading slate/slate-react to mismatched versions.

Related errors

• [Slate] initialValue is invalid! Expected a list of elements
• Got non-numeric path index
• Got non-numeric path index
• Cannot get the relative path of [${path}] inside ancestor [$
• Index must be number

AI-assisted analysis of ianstormtaylor/slate@72a37c701e (2026-08-27). Data as JSON: /api/errors/8fb241a9270c9e40. Report an issue: GitHub.