// ==UserScript==
// @name StackOverflow Code Language Switcher
// @namespace https://github.com/Christopher-Hayes/stackoverflow-code-language-switcher
// @homepageURL https://github.com/Christopher-Hayes/stackoverflow-code-language-switcher
// @supportURL https://github.com/Christopher-Hayes/stackoverflow-code-language-switcher
// @description Adds a dropdown to code blocks in StackOverflow to switch the code language. Powered by GPT-3 AI.
// @match https://stackoverflow.com/questions/*
// @grant GM_getValue
// @grant GM_setValue
// @grant GM_addValueChangeListener
// @grant GM_setClipboard
// @version 1.0
// @author Chris Hayes
// @license GPL3
// ==/UserScript==
class LangConvert {
constructor() {
this.key = GM_getValue("openai_key", "");
if (!this.key || this.key === "your-openai-key-here") {
GM_setValue("openai_key", "your-openai-key-here");
console.error(
'"openai_key" not set in violent monkey script. Please get an OpenAI key and set this config value to use the OpenAI API.'
);
}
this.supportedLanguages = GM_getValue("supported_languages", [
"javascript",
"typescript",
"python",
"java",
"bash",
"css",
"scss",
"html",
"c",
"c++",
"c#",
"rust",
"go",
"kotlin",
"php",
"ruby",
"liquid",
"swift",
"react",
"vue",
"svelte",
"angular",
]);
GM_setValue("supported_languages", this.supportedLanguages);
this.previousConversions = {};
}
setKey(newKey) {
this.key = newKey;
}
setSupportedLanguages(newLanguages) {
this.supportedLanguages = newLanguages;
}
async makeGPT3Request(code, oldLang, newLang) {
const url = "https://api.openai.com/v1/completions";
const headers = {
"Content-Type": "application/json",
Authorization: `Bearer ${this.key}`,
};
// Uses Davinci 003 text-completion
// code-completion and edit were slower and didn't work as well
const body = {
model: "text-davinci-003",
prompt: `# Convert this${oldLang ? " from " + oldLang : ""} to ${newLang}
# ${oldLang ? oldLang : "Old"} version
${code}
# ${newLang} version`,
max_tokens: 1000,
};
const response = await fetch(url, {
method: "POST",
headers,
body: JSON.stringify(body),
});
console.log(
"[StackOverflow Code Language Switcher] Full OpenAI response:",
response
);
const data = await response.json();
console.log("[StackOverflow Code Language Switcher] Response data:", data);
let newCode = data.choices[0].text;
// if the first line is an empty newline, remove it
if (newCode.startsWith("\n")) {
newCode = newCode.slice(1);
}
// if the last line is an empty newline, remove it
if (newCode.endsWith("\n")) {
newCode = newCode.slice(0, -1);
}
return newCode;
}
getCodeElements() {
return Array.from(document.querySelectorAll(".s-prose pre code"));
}
setup() {
const codeElements = this.getCodeElements();
for (const codeElem of codeElements) {
const pre = codeElem.parentElement;
const div = document.createElement("div");
div.classList.add("lang-convert");
div.style = `
height: 0;
float: right;
margin-bottom: -20px;
display: block;
position: relative;
top: 10px;
right: 8px;
`;
// Show supported languages in dropdown
const select = document.createElement("select");
select.innerHTML = `${this.supportedLanguages
.slice(0, 20)
.map((lang) => `<option value="${lang}">${lang}</option>`)
.join("")}`;
select.style = `
background: #181818;
color: #999;
outline: none;
border: 0;
padding: .5em 0.7em;
border-radius: 7px;
font-size: 12px;
`;
// Change style of select element when hovered over
select.addEventListener("mouseenter", () => {
select.style.background = "black";
select.style.color = "white";
});
select.addEventListener("mouseleave", () => {
select.style.background = "#181818";
select.style.color = "#999";
});
div.appendChild(select);
// Add div before pre element
pre.parentElement.insertBefore(div, pre);
// Set default value of dropdown to the language of the code element
const lang = codeElem.className.split("-")[1];
select.value = lang;
this.previousConversions[lang] = codeElem.textContent;
select.addEventListener("change", async (e) => {
const oldLang = codeElem.className.split("-")[1];
const newLang = e.target.value;
if (oldLang === newLang) return;
// Show "converting" overlay message
const overlay = document.createElement("div");
overlay.style = `
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
background: rgba(0, 0, 0, 0.5);
display: flex;
justify-content: center;
align-items: center;
color: white;
font-size: 20px;
font-weight: bold;
`;
overlay.innerHTML = "Converting...";
pre.style.position = "relative";
pre.appendChild(overlay);
const oldCode = codeElem.textContent;
let newCode = "";
if (this.previousConversions[newLang]) {
newCode = this.previousConversions[newLang];
} else {
newCode = await this.makeGPT3Request(oldCode, oldLang, newLang);
this.previousConversions[newLang] = newCode;
}
GM_setClipboard(newCode);
codeElem.classList.remove(`language-${oldLang}`);
codeElem.classList.add(`language-${newLang}`);
codeElem.textContent = newCode;
// add a script to the page that will highlight the new code using window.hljs
// This must be injected to have access to the highlight.js object already loaded into StackOverflow
const codeID =
Math.random().toString(36).substring(2, 15) +
Math.random().toString(36).substring(2, 15);
codeElem.id = codeID;
const script = document.createElement("script");
script.innerHTML = `if (window.hljs) window.hljs.highlightElement(document.getElementById("${codeID}"));`;
document.body.appendChild(script);
// Remove "converting" overlay message
pre.removeChild(overlay);
pre.style.position = "static";
});
}
}
}
let langConvert = new LangConvert();
langConvert.setup();
GM_addValueChangeListener("openai_key", (name, oldValue, newValue) => {
langConvert.setKey(newValue);
});
GM_addValueChangeListener("supported_languages", (name, oldValue, newValue) => {
langConvert.setSupportedLanguages(newValue);
});
