Swift Requires Chilkat v11.4.0+

Call a JavaScript Function Returning a Boolean

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Demonstrates how to call a JavaScript function that returns a boolean. Swift

func chilkatTest() {
    var success: Bool = false

    //  This is the JavaScript function we'll call:

    //  function isEven(number) {
    //      return number % 2 === 0;
    //  }

    let sbScript = CkoStringBuilder()!
    sbScript.append(value: "function isEven(number) { return number % 2 === 0; }")

    let js = CkoJs()!

    let result = CkoJsonObject()!
    result.emitCompact = false

    //  Call Eval to add the function to the context's global object
    success = js.eval(jscript: sbScript, result: result)
    if success == false {
        //  Examine the result for an exception.
        print("\(result.emit()!)")

        //  Also examine the LastErrorText.
        print("\(js.lastErrorText!)")
        return
    }

    //  ------------------------------------------------------------------------------
    //  Call the function isEven(8)

    let funcCall = CkoJsonObject()!

    //  Create JSON specifying the function name and arguments

    //  {
    //    "name": "isEven",
    //    "args": [ 8 ]
    //  }

    funcCall.updateString(jsonPath: "name", value: "isEven")
    funcCall.updateInt(jsonPath: "args[0]", value: 8)

    success = js.callFunction(func: funcCall, result: result)
    if success == false {
        //  Examine the result for an exception.
        print("\(result.emit()!)")

        //  Also examine the LastErrorText.
        print("\(js.lastErrorText!)")
        return
    }

    print("\(result.emit()!)")

    //  Output:
    //  {
    //    "type": "bool",
    //    "value": true
    //  }

    var retval: Bool = result.bool(of: "value")
    print("\(retval)")

    //  Output:
    //  true

}