Add a script to check for dead code (#22793)

scripts/analyse_unused_exports.js

@@ -0,0 +1,42 @@
+#!/usr/bin/env node
+'use strict';
+
+const fs = require("fs");
+const { exec } = require("node:child_process");
+
+const ignore = [];
+
+ignore.push(...Object.values(JSON.parse(fs.readFileSync(`${__dirname}/../components.json`))));
+ignore.push("/index.ts");
+
+const command = `yarn ts-prune --ignore "${ignore.join("|")}" | grep -v "(used in module)"`;
+
+exec(command, (error, stdout) => {
+    if (error) throw error;
+
+    let lines = stdout.split("\n");
+    // Remove the first line as that is the command that was being run and we
+    // log that only in case of an error
+    lines.splice(0, 1);
+    // Remove the last line as it is empty
+    lines.pop();
+
+    // ts-prune has bug where if the unused export is in a dependency, the path
+    // won't have an "/" character at the start, so we try to fix that for
+    // better UX
+    // TODO: This might break on Windows
+    lines = lines.reduce((newLines, line) => {
+        if (!line.startsWith("/")) newLines.push("/" + line);
+        else newLines.push(line);
+        return newLines;
+    }, []);
+
+    // If an unused export has been found, we error
+    if (lines.length > 0) {
+        console.log(`Command that was run: ${command}`);
+        console.log(lines.join("\n"));
+        throw Error("Unused exports found!");
+    }
+
+    console.log("Success - no unused exports found!");
+});