title: How to "lock" a field value based on default value in a react Json Schema form?
body: <p>We have a json schema that includes a field, for which we want to control the value via the schema (rather than having the user specify the value).</p>
  
  <p>We can set a default value - but this is simply overwritten by the formData that the user parses. </p>
  
  <p>Is there a way to "lock" the field value to the default value provided in the schema, ensuring that the formData is updated with the schema-specified value?</p>
  
  <pre><code>{
   "meta": {
        "title": "SCHEMA REVISION",
        "type": "object",
        "properties": {
          "rev": {
            "title": "We want to lock the below default value via the schema",
            "type": "string",
            "default": "10.00"
          }
        }
      }
  }
  </code></pre>