How to use ionic.Platform in ionic3

I am currently upgrading a project from ionic v1 to ionic v3, but I am having trouble. ionic.Platform cannot be used in ionic3. Can someone tell me how to solve this problem?

enable() {
			console.log("bts : enabling...");
			if (ionic.Platform.isIOS()) {
				console.log("bts : iOS...");
				return null;
			} else {
				console.log("bts : non-iOS...");
				return this.Ble.enable();
constructor(private platform: Platform) {
  if ('ios')) {
    // ios platform
  } else {
    //not ios platform

Thank you, this is useful to me.