限制来自 javascript fetch 的 fetch 结果

Question

Is there a function similar to q=sort& or q=created:& to limit number of results from a JavaScript fetch?

fetch('https://jsonplaceholder.typicode.com/posts')
  .then((res) => res.json())
  .then((data) => { }

Answer 1

The best solution, of course, is if the https://jsonplaceholder.typicode.com/posts endpoint documents a limit or filter parameter you can send it.

Assuming the result is an array, or contains an array, the very-much-second-best solution is to filter the result (to apply criteria) and/or slice the result (to just apply a limit):

fetch('https://jsonplaceholder.typicode.com/posts')
    .then((res) => res.json())
    .then((data) => {
        data = data.filter(entry => entry.created > someValue) // Created after X
                   .slice(0, 1000);                            // Limit to 1000
        // ...use data...
    })
    .catch(error => {        // <=== Don't forget to handle errors
        // Handle error...
    });

---

Note: Your fetch call is missing a check on res.ok (it's not just you, a lot of people make that mistake so many that I wrote it up on my anemic little blog ):

fetch('https://jsonplaceholder.typicode.com/posts')
    .then((res) => {                                      // ***
        if (!res.ok) {                                    // ***
            throw new Error("HTTP error " + res.status);  // ***
        }                                                 // ***
    })                                                    // ***
    .then((res) => res.json())
    .then((data) => {
        data = data.filter(entry => entry.created > someValue)
                   .slice(0, 1000);
        // ...use data...
    })
    .catch(error => {
        // Handle error...
    });

Answer 2

From https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch :

postData(`http://example.com/answer`, {answer: 42})
  .then(data => console.log(JSON.stringify(data))) // JSON-string from `response.json()` call
  .catch(error => console.error(error));

function postData(url = ``, data = {}) {
  // Default options are marked with *
    return fetch(url, {
        method: "POST", // *GET, POST, PUT, DELETE, etc.
        mode: "cors", // no-cors, cors, *same-origin
        cache: "no-cache", // *default, no-cache, reload, force-cache, only-if-cached
        credentials: "same-origin", // include, same-origin, *omit
        headers: {
            "Content-Type": "application/json; charset=utf-8",
            // "Content-Type": "application/x-www-form-urlencoded",
        },
        redirect: "follow", // manual, *follow, error
        referrer: "no-referrer", // no-referrer, *client
        body: JSON.stringify(data), // body data type must match "Content-Type" header
    })
    .then(response => response.json()); // parses response to JSON
}

Not sure what exactly you want so here are 3 possibilities:

1. You can add a payload to the body of the fetch, see above.

2. You could simply url-encode it.

3. On res.json()) .then((data) => { } ... You can filter the data you want.

Hope this helps.