Objective: Clean messy text data using expressions so the email and role fields become neat and consistent.

• Nodes Used: When clicking "Execute Workflow" → Create Messy Data → Clean Data (Expression)
• Concept: Data cleaning with expressions using $json, toLowerCase() and trim().
• Exercise Steps:
  • [ ] Create a new workflow named Lab 3 - Data Transformer.
  • [ ] Add a Manual Trigger node and rename it to When clicking "Execute Workflow".
  • [ ] Add a Set node called Create Messy Data and add:
    • Email = STUDENT@GMAIL.COM
    • Role = admin (with spaces before and after)
  • [ ] Add another Set node called Clean Data (Expression).
  • [ ] In Clean Data (Expression) add:
    • Clean_Email as an expression {{ $json.Email.toLowerCase() }}
    • Clean_Role as an expression {{ $json.Role.trim() }}
  • [ ] Execute the workflow and compare the output of Create Messy Data and Clean Data (Expression) to see the before and after.
  • [ ] Optional for trainers: add a Sticky Note called Instructions to remind yourself to demonstrate drag and drop into the Expression Editor before adding .toLowerCase() and .trim().

{
  "nodes": [
    {
      "parameters": {},
      "id": "159d53e0-c742-4fd3-a163-c924b21266d0",
      "name": "When clicking \\"Execute Workflow\\"",
      "type": "n8n-nodes-base.manualTrigger",
      "typeVersion": 1,
      "position": [
        -304,
        32
      ]
    },
    {
      "parameters": {
        "assignments": {
          "assignments": [
            {
              "id": "messy-email",
              "name": "Email",
              "value": "STUDENT@GMAIL.COM",
              "type": "string"
            },
            {
              "id": "messy-role",
              "name": "Role",
              "value": "   admin   ",
              "type": "string"
            }
          ]
        },
        "options": {}
      },
      "id": "1a4d3fed-9a50-44ee-8ba7-46daecac3df4",
      "name": "Create Messy Data",
      "type": "n8n-nodes-base.set",
      "typeVersion": 3.4,
      "position": [
        -80,
        32
      ]
    },
    {
      "parameters": {
        "assignments": {
          "assignments": [
            {
              "id": "clean-email",
              "name": "Clean_Email",
              "value": "={{ $json.Email.toLowerCase() }}",
              "type": "string"
            },
            {
              "id": "clean-role",
              "name": "Clean_Role",
              "value": "={{ $json.Role.trim() }}",
              "type": "string"
            }
          ]
        },
        "options": {}
      },
      "id": "d49eec3a-e828-4956-b8e5-dc8e28d50e33",
      "name": "Clean Data (Expression)",
      "type": "n8n-nodes-base.set",
      "typeVersion": 3.4,
      "position": [
        128,
        32
      ]
    },
    {
      "parameters": {
        "content": "## Lab 3: Data transformer (expressions)\\n1. **Create Messy Data:** Simulates bad data entry (Caps, Spaces).\\n2. **Clean Data:** Uses Expressions.",
        "height": 452,
        "width": 780,
        "color": 5
      },
      "id": "dd58e9a7-7a1c-4f1d-9bd5-c9bf4d04507f",
      "type": "n8n-nodes-base.stickyNote",
      "typeVersion": 1,
      "position": [
        -432,
        -160
      ],
      "name": "Instructions"
    }
  ],
  "connections": {
    "When clicking \\"Execute Workflow\\"": {
      "main": [
        [
          {
            "node": "Create Messy Data",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Create Messy Data": {
      "main": [
        [
          {
            "node": "Clean Data (Expression)",
            "type": "main",
            "index": 0
          }
        ]
      ]
    }
  },
  "pinData": {},
  "meta": {
    "instanceId": "82cc682d3f33add4f11a78e1f29750bf4ba4e425478ba4b17330f9bf15960ec6"
  }
}