packages/node_modules/pouchdb-utils/src/once.js

function once(fun) {
  var called = false;
  return function (...args) {
    /* istanbul ignore if */
    if (called) {
      // this is a smoke test and should never actually happen
      throw new Error('once called more than once');
    } else {
      called = true;
      fun.apply(this, args);
    }
  };
}

export default once;