If we need to convert a string value "true" or "false" to a boolean we can use the toBoolean function from the dw::util::Coercions module. The function will return a boolean true if the string value is "true", mixed casing is allowed. And the function returns false for a mixed casing string value of "false". Any other string value will throw an exception and will not return a boolean value.

In the following example we coerce some string values to a boolean and also include an example where the input value cannot be coerced:

Source

%dw 2.0

import try from dw::Runtime
import toBoolean from dw::util::Coercions

output application/json
---
{
    // Coerce all string values to a boolean with value true.
    trueBooleans: ["TRUE", "true", "True", "trUE"] map (s) -> toBoolean(s),

    // Coerce all string value to a boolean with value false.
    falseBooleans: ["FALSE", "false", "False", "falSE"] map toBoolean($),

    // An exception is thrown when the string value cannot be coerced.
    invalidCoercion: try(() -> toBoolean("Yes"))
}

Output

{
  "trueBooleans": [
    true,
    true,
    true,
    true
  ],
  "falseBooleans": [
    false,
    false,
    false,
    false
  ],
  "invalidCoercion": {
    "success": false,
    "error": {
      "kind": "InvalidBooleanException",
      "message": "Cannot coerce String (Yes) to Boolean",
      "location": "\n16|     invalidCoercion: try(() -> toBoolean(\"Yes\"))\n
                                                                   ^^^^^",
      "stack": [
        "toBoolean (main:16:42)",
        "main (main:16:32)"
      ]
    }
  }
}
DataWeave is a functional language designed by MuleSoft for transforming data structures defined in for example JSON, XML or CSV.

Written with DataWeave 2.4.

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