Swift

Call a JavaScript Function Returning a String

See more JavaScript Examples

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

func chilkatTest() {
    var success: Bool = false

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

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

    let sbScript = CkoStringBuilder()!
    sbScript.append(value: "function greet(name) { return \"Hello, \" + name + \"!\"; }")

    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 greet("Michael")

    let funcCall = CkoJsonObject()!

    // Create JSON specifying the function name and arguments

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

    funcCall.updateString(jsonPath: "name", value: "greet")
    funcCall.updateString(jsonPath: "args[0]", value: "Michael")

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

    var retval: String? = result.string(of: "value")
    print("\(retval!)")

    // Output:
    // Hello, Michael!

}