调用api函数发送请求，若5秒后未请求成功，则调用warning函数发出警告。其中，api函数在请求成功的情况下会返回一个promise使用javascript编程实现

Sure, here is a possible implementation using JavaScript:

function sendRequestWithTimeout(apiFunction, timeout) {
  let timeoutId;
  const promise = new Promise((resolve, reject) => {
    // Set timeout
    timeoutId = setTimeout(() => {
      reject('Request timed out');
    }, timeout);

    // Call API function
    apiFunction().then((response) => {
      resolve(response);
    }).catch((error) => {
      reject(error);
    });
  });

  // Cancel timeout when request is fulfilled
  promise.finally(() => clearTimeout(timeoutId));

  return promise;
}

function apiFunction() {
  // Call API function here and return a Promise
}

function warning() {
  // Show warning message or take any other action
}

sendRequestWithTimeout(apiFunction, 5000).then((response) => {
  // Handle successful response here
}).catch((error) => {
  if (error === 'Request timed out') {
    warning();
  } else {
    // Handle other errors
  }
});

In the above code, `sendRequestWithTimeout` is a wrapper function that takes an `apiFunction` and a `timeout` in milliseconds. It returns a Promise that resolves with the response if the `apiFunction` is successful within the timeout period, or rejects with an error message if the `apiFunction` fails or takes longer than the timeout period. The timeout is implemented using `setTimeout`, and is cancelled when the Promise is fulfilled (whether resolved or rejected).

You can use this function to wrap any API function that returns a Promise, like so:

sendRequestWithTimeout(() => fetch('https://example.com/api/data'), 5000)

Note that this code doesn't make any requests or handle any warnings directly, it only provides a reusable function to wrap API calls with a timeout. You'll need to adapt it to your specific use case by replacing `apiFunction` and `warning` with your own implementations.