title: How to add escape character in mule data weave transformation
body: <p>I want to do below transformation. I am struggling to add escape character in data weave. I am able to merge the payload into a single string but can't add escape character.</p>
  
  <p>Input</p>
  
  <pre><code> {
     "request":{
        "Id":"1111",
        "channel":"ABC",
        "useFilters":false
     },
     "need":{
        "postcode":2222,
        "Imp":"Mobile",
        "additionalProducts":[
  
        ],
        "isOwner":true,
        "isMovingIn":true,
        "movingDate":"2017-07-28",
        "otherNeeds":[
           "Food",
           "Car"
        ]
     },
     "filter":{
        "productType":[
  
        ],
        "zone":[
  
        ],
        "data":[
  
        ],
        "speedTier":[
  
        ],
        "recommendedPlans":true
     }
  }
  </code></pre>
  
  <p>Output</p>
  
  <pre><code>{
   "needs": {
        "key": "capture_value",
        "value": "{\"request\":{\"Id\":\"1111\",\"channel\":\"ABC\",\"useFilters\":false},\"need\":{\"postcode\":2222,\"Imp\":\"Mobile\",\"additionalProducts\":[],\"isOwner\":true,\"isMovingIn\":true,\"movingDate\":\"2017-07-28\",\"otherNeeds\":[\"Food\",\"Car\"]},\"filter\":{\"productType\":[],\"zone\":[],\"data\":[],\"speedTier\":[],\"recommendedPlans\":true}}"
      }
    }
  </code></pre>
  
  <p>Can anyone please suggest how to do the above transformation?
  TIA</p>