How to implement GET requests for multiple links in Tampermonkey and determine the conditions in sequence?

Tampermonkey handles multiple GET requests in sequence and makes conditional judgments

In the Tampermonkey script, GET requests need to be initiated for multiple links, and conditions are made according to the returned results, until the conditions are met or all links are processed. Directly using GM_xmlhttpRequest to concurrent requests cannot meet the "order judgment" requirement, because GM_xmlhttpRequest itself does not support canceling requests. Therefore, we need to adopt the serial request method.

The following two implementation methods are provided:

Method 1: Use Promise chain call to implement serial requests

This method uses the then method of Promise to realize serial execution and conditional judgment of requests.

 async function processLinks(links, conditionFunc) {
  for (const link of links) {
    const response = await fetch(link); // Use fetch instead of GM_xmlhttpRequest to more modernize const data = await response.text(); // Get the response text if (conditionFunc(data)) {
      return data; // The condition is met, return the result and end}
  }
  return null; // No link meets the conditions}

// Example usage:
const links = [
  "https://example.com/link1",
  "https://example.com/link2",
  "https://example.com/link3"
];

const condition = (data) => data.includes("success"); // The determination condition function processLinks(links, condition)
  .then((result) => {
    if (result) {
      console.log("The condition is satisfied, result:", result);
    } else {
      console.log("All links do not meet the criteria");
    }
  })
  .catch((error) => {
    console.error("Request error:", error);
  });

Method 2: Use recursive functions to implement serial requests

This method uses a recursive function, processing one link at a time, and ends recursion after the condition is met or all links are processed.

 function processLinksRecursive(links, conditionFunc, index = 0, result = null) {
  if (index >= links.length || result !== null) {
    return result; // End recursion}

  fetch(links[index])
    .then(response => response.text())
    .then(data => {
      if (conditionFunc(data)) {
        result = data; // The condition is met} else {
        result = processLinksRecursive(links, conditionFunc, index 1, result); // Continue to recursion}
    })
    .catch(error => console.error("Request error:", error));

  return result; // Return result}

// Example usage (same as method one):
const links = [
  "https://example.com/link1",
  "https://example.com/link2",
  "https://example.com/link3"
];

const condition = (data) => data.includes("success");

const finalResult = processLinksRecursive(links, condition);
if (finalResult) {
  console.log("The condition is satisfied, result:", finalResult);
} else {
  console.log("All links do not meet the criteria");
}

Note: The above code uses fetch API, which is more modern and easier to use than GM_xmlhttpRequest . If your Tampermonkey environment does not support fetch , you need to replace GM_xmlhttpRequest and adjust the code accordingly. In addition, remember to modify the conditionFunc function according to your actual situation and define your condition judgment logic. Both methods achieve the purpose of sequential requests and judgments. Which method to choose depends on your personal preferences. Method 1 is more concise and easy to read, and Method 2 is closer to the classic pattern of recursion.

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