Fallback

The fallback feature allows you to specify a default value to be returned when a query does not return any data

TIP

You can set the fallback value in the config object as well.

The fallback value in query will have a higher priority than the one in the config object.

Fall Mark

The fall mark token ?? is used to define the fallback value inside the query. Everything after fall mark will be considered as fallback value

$.user.phone ?? No phone provided

Return Value

The returned value will be the fallback string

"Fallback value"

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Sample Data

{
  "name": "John",
  "favorites": {
    "color": "blue",
    "food": "pizza",
    "place": null
  }
}

Queries

query.run("$.favorites.game ?? No favorite game") // "No favorite game"
query.run("$.favorites.color ?? No favorite color") // "blue"
query.run("$.favorites.place ?? No favorite place") // null

INFO

If the value is null, it will be returned as is, not the fallback value.