REACTJS: Change loader API URL based on Rout path in React

Question

To reuse a component that loads different data in same format, same element is rendered in different path. How to change url based on route path in EmpPage.js

App.js:

    {
    path: "emp-detail",
    element: <EmpRootLayout />,
    children: [
      {
        index: true,
        element: <EmpPage />,
        loader: empListLoader,
      },
      {
        path: "retired",
        element: <EmpPage  />,
        loader: empListLoader,
      },
      {
        path: "resigned",
        element: <EmpPage />,
        loader: empListLoader,
      },
    ],

EmpPage.js

async function loadEmpRequests() {
  // change url based on route path
  let url = "http://localhost:8000/empData";
  const response = await fetch(url, {
    method: "GET",
  });

  const resData = await response.json();
  return resData.data;
  
}

export function loader() {
  return defer({
    empRequests: loadEmpRequests(),
  });
}

Answer 1

It seems you have a lot of code duplication here. I'd suggest rendering a single route with a dynamic route parameter that can be read in the loader function.

Example:

{
  path: "emp-detail",
  element: <EmpRootLayout />,
  children: [
    {
      path: ":page?", // <-- optional dynamic segment
      element: <EmpPage />,
      loader: empListLoader,
    },
  ],
}

https://reactrouter.com/en/main/route/route#optional-segments

async function loadEmpRequests({ params }) {
  const { page } = params;

  // change url based on route path parameter
  let url = "";
  switch(page) {
    case "retired":
      url = ".....";
      break;

    case "resigned":
      url = ".....";
      break;

    default:
      url = ".....";
      break;

  }
  
  const response = await fetch(url, {
    method: "GET",
  });

  const { data } = await response.json();
  return data;
}

An alternative might also be to make the loader a curried function and the URL can be passed in as a parameter.

Example:

{
  path: "emp-detail",
  element: <EmpRootLayout />,
  children: [
    {
      index: true,
      element: <EmpPage />,
      loader: empListLoader("...."),
    },
    {
      path: "retired",
      element: <EmpPage  />,
      loader: empListLoader("...."),
    },
    {
      path: "resigned",
      element: <EmpPage />,
      loader: empListLoader("...."),
    },
  ],
}

function loadEmpRequests(url) {
  return async function() {
    const response = await fetch(url, {
      method: "GET",
    });

    const { data } = await response.json();
    return data;
  }
}