Dynamic JSON

In areas where Retool expects an object type input, you can use a superset of JSON to specify the object. Here are some examples of expressions that work (click on the JSON tab to see the evaluation):

Normal ES5 JSON

Single quotes are supported.

"a string";
"another string";

"a string"
"another string"

Keys do not need to be in double quotes.

{
  a: 1;
}

{ "a": 1 }

Numbers with decimals are supported.

1023.24;

1023.24

Trailing commas, single-line, and multi-line comments are allowed.

{
  // name of user
  name: 'Sarah',
  age: 24,
  /* list of roles user owns
  note that user can have multiple roles */
  roles: [
    { id: 1, name: 'engineer' },
    { id: 2, name: 'admin' },
  ],
}

{
  "name": "Sarah",
  "age": 24,
  "roles": [
    {
      "id": 1,
      "name": "engineer"
    },
    {
      "id": 2,
      "name": "admin"
    }
  ]
}

Dynamic properties using `{{ }}`

You can use any valid expression inside {{ }} in your JSON.

{
  name: {{ true ? 'Mary' : 'Chris' }},
  description: "Owns {{ 2 }}  {{ 'films' }}",
  owned_films: {{ ['Jaws', 'Star Wars' ] }},
  metadata: {{ { a: 1, b: 2, c: [] } }},
}

{
  "name": "Mary",
  "description": "Owns 2 films",
  "owned_films": ["Jaws", "Star Wars"],
  "metadata": {
    "a": 1,
    "b": 2,
    "c": []
  }
}

Dynamically adding properties to an object

Remove a key by setting the value to undefined.

{
  shouldShow: {{ true  ? 'Hi 👋'  : undefined }},
  shouldHide: {{ false ? 'Bye 👻' : undefined }},
}

{
  "shouldShow": "Hi 👋"
}

Normal ES5 JSON

Dynamic properties using {{ }}

Dynamically adding properties to an object

Dynamic properties using `{{ }}`