JavaScript 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. JavaScript

var success = false;

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

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

var sbScript = new CkStringBuilder();
sbScript.Append("function isEven(number) { return number % 2 === 0; }");

var js = new CkJs();

var result = new CkJsonObject();
result.EmitCompact = false;

//  Call Eval to add the function to the context's global object
success = js.Eval(sbScript,result);
if (success == false) {
    //  Examine the result for an exception.
    console.log(result.Emit());

    //  Also examine the LastErrorText.
    console.log(js.LastErrorText);
    return;
}

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

var funcCall = new CkJsonObject();

//  Create JSON specifying the function name and arguments

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

funcCall.UpdateString("name","isEven");
funcCall.UpdateInt("args[0]",8);

success = js.CallFunction(funcCall,result);
if (success == false) {
    //  Examine the result for an exception.
    console.log(result.Emit());

    //  Also examine the LastErrorText.
    console.log(js.LastErrorText);
    return;
}

console.log(result.Emit());

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

var retval = result.BoolOf("value");
console.log(retval);

//  Output:
//  true