memoize3.mjs

/**
 * Memoizes the provided three-argument function.
 */
export default function memoize3(fn) {
  var cache0;

  function memoized(a1, a2, a3) {
    if (!cache0) {
      cache0 = new WeakMap();
    }

    var cache1 = cache0.get(a1);
    var cache2;

    if (cache1) {
      cache2 = cache1.get(a2);

      if (cache2) {
        var cachedValue = cache2.get(a3);

        if (cachedValue !== undefined) {
          return cachedValue;
        }
      }
    } else {
      cache1 = new WeakMap();
      cache0.set(a1, cache1);
    }

    if (!cache2) {
      cache2 = new WeakMap();
      cache1.set(a2, cache2);
    }

    var newValue = fn(a1, a2, a3);
    cache2.set(a3, newValue);
    return newValue;
  }

  return memoized;
}