Node.js

Call a JavaScript Function Returning a String

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Demonstrates how to call a JavaScript function that returns a string. Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

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

    // function greet(name) {
    //     return "Hello, " + name + "!";
    // }

    var sbScript = new chilkat.StringBuilder();
    sbScript.Append("function greet(name) { return \"Hello, \" + name + \"!\"; }");

    var js = new chilkat.Js();

    var result = new chilkat.JsonObject();
    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 greet("Michael")

    var funcCall = new chilkat.JsonObject();

    // Create JSON specifying the function name and arguments

    // {
    //   "name": "greet",
    //   "args": [ "Michael" ]
    // }

    funcCall.UpdateString("name","greet");
    funcCall.UpdateString("args[0]","Michael");

    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": "string",
    //   "value": "Hello, Michael!"
    // }

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

    // Output:
    // Hello, Michael!

}

chilkatExample();