update-matrix-room-permissions.mjs

import fs from 'fs';
import { inspect } from 'util';
import path from 'path';
import { fileURLToPath } from 'url';

let __dirname = path.dirname(fileURLToPath(import.meta.url));

let usersToUpgrade = ['@justingrant:matrix.org'];
let targetPowerLevel = 50;
let roomId = '!nSLHQtIRJQxUJbEuGt:matrix.org'; // editor channel; this ID can be obtained from room settings -> Advanced


/*
Obtain your access token. On the Element.io web app, this is under Settings -> Help & About (yes, really).
Put it in a file in this directory named access_token.txt.
*/
let accessToken = fs.readFileSync(path.resolve(__dirname, 'access_token.txt'), 'utf8').trim();

async function api(path) {
  return (await fetch('https://matrix.org/_matrix/client/v3/' + path, {
    headers: {
      'Authorization': `Bearer ${accessToken}`,
    },
  })).json();
}

let powerLevels = await api(`rooms/${roomId}/state/m.room.power_levels`);

for (let user of usersToUpgrade) {
  if ((powerLevels.users[user] ?? 0) < targetPowerLevel) {
    powerLevels.users[user] = targetPowerLevel;
  }
}

let response = await (await fetch(`https://matrix.org/_matrix/client/v3/rooms/${roomId}/state/m.room.power_levels`, {
  method: 'PUT',
  headers: {
    'Content-Type': 'application/json',
    'Authorization': `Bearer ${accessToken}`,
  },
  body: JSON.stringify(powerLevels),
})).json();
console.log(response);