d3未捕获TypeError:放大。x不是一个函数。

I am trying to implement tooltips and a zoom on a graph, the tooltips work fine however I am having issues with the zoom function. I get an error on the debugger that says: Uncaught TypeError: zoomed.x is not a function. This occurs at the line 'return zoomed.x(x);' I am not sure how to change the code to get it to work. I am trying to implement tooltips and a zoom on