BUI Pass Field Value in Link or Extension

Content

In the BUI, we are unable to pass the value of a field through a link. The values return null. As a workaround, I am trying to build a button add-in that will read the value of the field and open a new tab with the field values in the url. Does anyone have any tips to help me get started? So far I have been able to add the button to the GlobalHeaderMenu, but now I want it to read field values when it is pressed. My code seems to have broken the button.

Code Snippet

ORACLE_SERVICE_CLOUD.extension_loader.load("GlobalHeaderMenuItem", "1.0").then(function (sdk) {
    sdk.registerUserInterfaceExtension(function (IUserInterfaceContext) {
        IUserInterfaceContext.getGlobalHeaderContext().then(function (IGlobalHeaderContext) {
            IGlobalHeaderContext.getMenu('').then(function (IGlobalHeaderMenu) {
                var icon = IGlobalHeaderMenu.createIcon("font awesome");
                icon.setIconClass("fas fa-thumbs-up");
                IGlobalHeaderMenu.addIcon(icon);