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GM_fetch
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| /*********** | |
| This is not a 100% 1:1 mapping to fetch, | |
| but it works good enough for most use cases! | |
| How to use: | |
| Just copy and paste this function into your Userscript. | |
| Then, call it as you would normal `fetch`. | |
| ************/ | |
| async function GM_fetch(url, options = {}) { | |
| return new Promise(resolve => { | |
| GM_xmlhttpRequest({ | |
| ...options, | |
| headers: { | |
| 'Content-Type': 'application/json', | |
| ...(options.headers || {}) | |
| }, | |
| url, | |
| data: options.body, | |
| onerror: () => throw new Error('Error'), | |
| ontimeout: () => throw new Error('Timeout'), | |
| onload: (xhr) => { | |
| xhr.json = function() { | |
| const xhrThis = this; | |
| const jsonPromise = new Promise(resolve => { | |
| let parsed; | |
| try { | |
| parsed = JSON.parse(xhrThis.responseText); | |
| } catch(e) { | |
| throw new Error('Could not JSON decode'); | |
| } | |
| resolve(parsed); | |
| }); | |
| return jsonPromise; | |
| } | |
| resolve(xhr); | |
| }, | |
| }); | |
| }); | |
| }; | |
| /*************** | |
| How to use it | |
| ****************/ | |
| const resp = await GM_fetch('https://xxxxx.com', { | |
| method: 'POST', | |
| headers: { | |
| 'api-key': 'xxxxxxxxxxxxxxxxxxxx', | |
| }, | |
| body: JSON.stringify(body), | |
| }); | |
| const decoded = await resp.json(); |
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This definitely is not a 100% 1:1 mapping to
fetch, but it works good enough in Greasemonkey / Tampermonkey / Violentmonkey scripts. Great for making requests to bypass CORS.Remember to add this to your script header in order for it to work
// @grant GM_xmlhttpRequestFeel free to leave comments/suggestions for improvement.