Function cached

src/core/util/core.js:7–14

(fn)

 */

export function cached(fn) {
  const cache = Object.create(null);
  return function (str) {
    const key = isPrimitive(str) ? str : JSON.stringify(str);
    const hit = cache[key];
    return hit || (cache[key] = fn(str));
  };
}

/**
 * Hyphenate a camelCase string.