The findFirst function finds the first object from an array based on some condition.

Syntax

firstValFound = findFirst(array, booleanExpression)

Inputs

array : a reference to an array.

booleanExpression : conditional expression to find an object in the array.

Output

firstValFound : the first value in the array that caused the boolean expression to evaluate to true.

Example flow

Schema w2Schema {
  w2 [
    string employerName
    number wages
  ]
}

Schema Outcome {
    string employerName
    number wages
}

value income -> w2Schema {
  w2 [
     {
       "Intuit, Inc.
       105000
     }
     {
       "Uber
       10000
     }
  ]
}

Schema thresholdSchema {
  number wages
}

value threshold -> thresholdSchema { 100000 }

Mapping finalMapping input income, threshold output Outcome as output {
  output = findFirst(income.w2, employerName == "Intuit, Inc." && wages > ::threshold.wages)
}

Flow filterFlow {      
  Start finalMapping {
  }
}

Output for Example Flow

{ employerName : "Intuit, Inc.", wages : 105000 }

Explanation

The condition is employerName == "Intuit, Inc." && wages > ::threshold.wages.

The first part of the condition says employerName == "Intuit, Inc.". The context of the variable employerName here is the array, which is income.w2. (You don't have to specify the whole path i.e income.w2.employerName to filter the w2s).

The second part of the condition says wages > ::threshold.wages". The variable wages here is within the context of w2 but if you want to refer something which is outside the scope of w2, you need to refer it with a global scope operator ::