FlowiseAI/Flowise · error · Error

Document object must contain pageContent and metadata

Error message

Document object must contain pageContent and metadata

What it means

CustomDocumentLoader ran the user's javascriptFunction in a sandbox and the output was an array (output='document'), but the first element does not satisfy the document shape: pageContent must be a string AND metadata must be an object. This is a contract check on sandbox output, not a network or parse error.

Source

Thrown at packages/components/nodes/documentloaders/CustomDocumentLoader/CustomDocumentLoader.ts:134

        }

        const sandbox = createCodeExecutionSandbox(input, variables, flow, additionalSandbox)

        try {
            const response = await executeJavaScriptCode(javascriptFunction, sandbox, {
                libraries: ['axios']
            })

            if (output === 'document' && Array.isArray(response)) {
                if (response.length === 0) return response
                if (
                    response[0].pageContent &&
                    typeof response[0].pageContent === 'string' &&
                    response[0].metadata &&
                    typeof response[0].metadata === 'object'
                )
                    return response
                throw new Error('Document object must contain pageContent and metadata')
            }

            if (output === 'text' && typeof response === 'string') {
                return handleEscapeCharacters(response, false)
            }

            return response
        } catch (e) {
            throw new Error(e)
        }
    }
}

module.exports = { nodeClass: CustomDocumentLoader_DocumentLoaders }

View on GitHub (pinned to abe4a8601a)

Solutions

1. Map every element explicitly: return response.data.map(item => ({ pageContent: String(item.text), metadata: { id: item.id } })).
2. Ensure pageContent is coerced to a string and metadata is always an object (use {} as fallback if you want it to pass).
3. Test the sandbox function standalone with a sample input before wiring it into the node.

Example fix

// before
// user function returned: [{ text: 'hi' }]
// after - shape each row to the contract
const docs = response.data.map((item) => ({
  pageContent: String(item.text ?? ''),
  metadata: { id: item.id, source: item.url }
}))
return docs

import type { IDocument } from './types'

function isDocumentArray(value: unknown): value is IDocument[] {
  if (!Array.isArray(value) || value.length === 0) return false
  return value.every((item) =>
    item !== null && typeof item === 'object'
    && typeof (item as any).pageContent === 'string'
    && (item as any).metadata !== null && typeof (item as any).metadata === 'object'
  )
}
// if (output === 'document' && isDocumentArray(response)) return response
// else throw with available-fields diagnostics

When it happens

Trigger: The function returned [{text: ...}] instead of [{pageContent, metadata}]; pageContent is a number or undefined; metadata is missing or is a string; the function returned the raw axios response object instead of mapped documents.

Common situations: User wrote the sandbox function against a different schema; the API they fetched from returned objects that were not mapped; only checked length>0 but element shape is wrong.

Related errors

• ${e}
• Invalid JSON in the Custom Document Loader Input Variables:
• Returned message history must be an array
• Security validation failed: ${error.message}
• ${e}

AI-assisted analysis of FlowiseAI/Flowise@abe4a8601a (2026-08-12). Data as JSON: /api/errors/811f71f42036567d. Report an issue: GitHub.