WonderfulLeafyReality created by habbes1 - https://repl.it/@habbes1/WonderfulLeafyReality

index.js

const hasAtMostOneAllowedKey = (arg, allowedKeys) => {
  const [firstKey, ...otherKeys] = allowedKeys;
  if (!firstKey) {
    return true;
  }
  if (firstKey in arg) {
    return !otherKeys.some(otherKey => otherKey in arg);
  }
  else {
    return hasAtMostOneAllowedKey(arg, otherKeys);
  }
}

const exclusiveKeys = ['tags', 'addTags', 'removeTags'];

function testWith(arg, expected) {
  const res = hasAtMostOneAllowedKey(arg, exclusiveKeys);
  if (res == expected) console.log("SUCCESS");
  else console.error(`ERROR: expected ${expected} but got ${res}`);
}

testWith({ tags: [] }, true);
testWith({ }, true);
testWith({ a: 1, tags: [] }, true);
testWith({ a: 2, tags: [], addTags: [] }, false);
testWith({ a: 1, addTags: []}, true)
testWith({ a: 1, removeTags: [] }, true);
testWith({ a: 1, addTags: [], removeTags: []}, false);