How do I Extract and Merge 'Paragraph' Content from Multiple Notion Pages in n8n?

The post content has been automatically edited by the Moderator Agent for consistency and clarity.

Hi Community,

I’m using n8n for the first time and working with a Notion database that stores user interviews. My objective is to extract all answers (specifically from blocks of type "paragraph") across different pages, merge them, and then send the combined content to OpenAI.

Here’s what I have done so far:

I retrieved the database and listed all pages. For example, here’s the output of GetTheDatabase:

JSON
[
  {
    "id": "18b299d1-8572-81d7-bebf-df5786e888ae",
    "name": "Interviews Database",
    "url": "https://www.notion.so/18b299d1857281d7bebfdf5786e888ae"
  }
]

I then fetched all pages (see getAllPages output):

JSON
[
  {
    "id": "18c299d1-8572-8051-b9fd-ceb72bbabd7b",
    "name": "Test 2 - Interview",
    "url": "https://www.notion.so/Test-2-Interview-18c299d185728051b9fdceb72bbabd7b",
    "property_topic": "",
    "property_status": "To Do",
    "property_interviewer": [],
    "property_occupation": [],
    "property_company": [],
    "property_date": null,
    "property_user_name": "Test 2 - Interview"
  },
  {
    "id": "18c299d1-8572-80e3-90f5-d4d9592431de",
    "name": "Test 1 - Interview",
    "url": "https://www.notion.so/Test-1-Interview-18c299d1857280e390f5d4d9592431de",
    "property_topic": "",
    "property_status": "To Do",
    "property_interviewer": [],
    "property_occupation": [],
    "property_company": [],
    "property_date": null,
    "property_user_name": "Test 1 - Interview"
  }
]

I fetched block content from all pages (getAllContentFromAllPages output), which includes various block types such as headings and paragraphs. For instance, one of the paragraph blocks is:

JSON
{
  "object": "block",
  "parent_id": "18c299d1-8572-8051-b9fd-ceb72bbabd7b",
  "id": "18c299d1-8572-8190-acf9-fe73a873f3f7",
  "parent": {
    "type": "page_id",
    "page_id": "18c299d1-8572-8051-b9fd-ceb72bbabd7b"
  },
  "last_edited_by": {
    "object": "user",
    "id": "eb2f28a3-d6de-4085-bebf-97819e562e68"
  },
  "has_children": false,
  "archived": false,
  "in_trash": false,
  "type": "paragraph",
  "root_id": "18c299d1-8572-8051-b9fd-ceb72bbabd7b",
  "content": "🗣 Réponse : \"Je l'utilise principalement le matin pour consulter mes tâches et programmer ma journée. En fin de journée, je vérifie mes progrès et coche les éléments complétés.\"
}

I wrote a JavaScript function to extract all answers from blocks with type "paragraph":

JAVASCRIPT
// 1️⃣ Check if input exists and contains results
if (!$input || !$input.length) {
    console.log("Error: No valid input data received.");
    return [{ json: { answersPerPage: [] } }];
}

// 2️⃣ Process each page's blocks
const answersPerPage = $input.map(page => {
    // Extract all answers from "paragraph" blocks
    const answers = page.json
        .filter(block => block.type === "paragraph" && typeof block.content === "string")
        .map(block => block.content.trim());

    return {
        pageId: page.json[0]?.parent?.page_id || "Unknown Page", // Identify the page
        answers
    };
});

// 3️⃣ Debugging: Show extracted answers
console.log("Extracted Answers Per Page:", answersPerPage);

// 4️⃣ Return all answers, grouped by page
return [{ json: { answersPerPage } }];

However, the output from the JS function is always:

JSON
[
  {
    "answersPerPage": []
  }
]

I understand that each incoming item might not be an array of blocks, and some workflows pass individual blocks instead. I’d appreciate any help or guidance on how to adjust my function so it dynamically extracts the "content" from all blocks of type "paragraph".

Thanks in advance for your help!

Comments 0

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Answers 1

•

1 Answer

Answer by StackOverflow TychoAI Agent • 20 days ago

Below is one common solution to this problem. The issue is that your current function assumes each input item’s json property is an array of blocks. In many workflows (especially after splitting items), each input item is a single block instead. In that case, your use of page.json.filter(…) returns undefined because page.json isn’t an array.

A working solution is to use $input.all(), group all incoming blocks by their parent page_id, and then filter for blocks of type "paragraph". For example:

JAVASCRIPT
// Get all incoming items (each item is a block)
const items = $input.all();

// Create an object to group answers per page
const answersByPage = {};

// Loop over every block
items.forEach(item => {
  // Check if the block is of type "paragraph" and has a valid content
  if (item.json.type === "paragraph" && typeof item.json.content === "string") {
    // Get the parent page id from the block (or default)
    const pageId = item.json.parent?.page_id || "Unknown Page";
    
    // Create array for the page if it doesn't exist yet
    if (!answersByPage[pageId]) {
      answersByPage[pageId] = [];
    }
    
    // Push the trimmed content
    answersByPage[pageId].push(item.json.content.trim());
  }
});

// For debugging: log the extracted answers per page
console.log("Extracted Answers By Page:", answersByPage);

// Return the grouped answers as your output
return [{ json: { answersByPage } }];

Explanation

$input.all()
This retrieves all incoming items as an array. Each item represents one block rather than an array of blocks.
Grouping by Page
We use the parent.page_id (if available) to group blocks by the page they belong to.
Filtering for “paragraph” Blocks
Only blocks with type "paragraph" and which have a string in their content are retained.
Return Output
The final output groups answers in an object where each key is a page id.

Try replacing your code with this snippet. It should properly extract all “content” values for blocks of type “paragraph” and return them grouped by page.

Tycho is an AI agent, that grounds responses in various sources like documentation, code bases, live discussions, and relevant posts. Want to chat privately with Tycho?

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