Go

Call a JavaScript Function Returning a String

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Demonstrates how to call a JavaScript function that returns a string. Go

    success := false

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

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

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

    js := chilkat.NewJs()

    result := chilkat.NewJsonObject()
    result.SetEmitCompact(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.
        fmt.Println(*result.Emit())

        // Also examine the LastErrorText.
        fmt.Println(js.LastErrorText())
        sbScript.DisposeStringBuilder()
        js.DisposeJs()
        result.DisposeJsonObject()
        return
    }

    // ------------------------------------------------------------------------------
    // Call the function greet("Michael")

    funcCall := chilkat.NewJsonObject()

    // 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.
        fmt.Println(*result.Emit())

        // Also examine the LastErrorText.
        fmt.Println(js.LastErrorText())
        sbScript.DisposeStringBuilder()
        js.DisposeJs()
        result.DisposeJsonObject()
        funcCall.DisposeJsonObject()
        return
    }

    fmt.Println(*result.Emit())

    // Output:
    // {
    //   "type": "string",
    //   "value": "Hello, Michael!"
    // }

    retval := result.StringOf("value")
    fmt.Println(*retval)

    // Output:
    // Hello, Michael!

    sbScript.DisposeStringBuilder()
    js.DisposeJs()
    result.DisposeJsonObject()
    funcCall.DisposeJsonObject()