Swift

Call a JavaScript Function Passing an Object Argument

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Demonstrates how to call a JavaScript function with an argument that is an object. Swift

func chilkatTest() {
    var success: Bool = false

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

    // function describeCar(car) {
    // 	console.log(`This is a ${car.year} ${car.make} ${car.model}.`);
    // }

    let sbScript = CkoStringBuilder()!
    sbScript.append(value: "function describeCar(car) { console.log(`This is a ${car.year} ${car.make} ${car.model}.`); }")

    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 describeCar(car)

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

    // Create JSON specifying the function name and arguments
    // In this case, there is only 1 argument, and it is an object.

    // {
    //   "name": "describeCar",
    //   "args": [
    //     {
    //       "make": "Toyota",
    //       "model": "Corolla",
    //       "year": 2022
    //     }
    //   ]
    // }

    funcCall.updateString(jsonPath: "name", value: "describeCar")

    // Create the JSON object that is the argument.
    let arg = CkoJsonObject()!
    arg.updateString(jsonPath: "make", value: "Toyota")
    arg.updateString(jsonPath: "model", value: "Corolla")
    arg.updateInt(jsonPath: "year", value: 2022)

    // Create the arguments array.
    let argsArray = CkoJsonArray()!
    argsArray.addObjectCopy(at: 0, jsonObj: arg)

    // Add the "args" array to the funcCall.
    funcCall.appendArrayCopy(name: "args", jarr: argsArray)

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

    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()!)")

    // The describeCar JavaScript function returns nothing. 
    // Therefore, the result is "undefined".

    // {
    //   "type": "undefined",
    //   "value": "undefined"
    // }

    // However, the function emitted text to the console.

    let sbOut = CkoStringBuilder()!
    js.consoleOutputSb(sb: sbOut)
    print("\(sbOut.getAsString()!)")

    // Output:
    // This is a 2022 Toyota Corolla.

    // -----------------------------------------------------------
    // Note: If the object argument is simple, this is an alternative
    // and simpler way of creating the funcCall:

    funcCall.clear()
    funcCall.updateString(jsonPath: "name", value: "describeCar")
    funcCall.updateString(jsonPath: "args[0].make", value: "Toyota")
    funcCall.updateString(jsonPath: "args[0].model", value: "Corolla")
    funcCall.updateInt(jsonPath: "args[0].year", value: 2022)
    print("\(funcCall.emit()!)")

}