unexpected/lib/addAdditionalPromiseMethods.js

Extensible BDD assertion toolkit

function addAdditionalPromiseMethods(promise, expect, subject) {
  promise.and = function(...args) {
    function executeAnd() {
      if (expect.findTypeOf(args[0]).is('expect.it')) {
        return addAdditionalPromiseMethods(args[0](subject), expect, subject);
      } else {
        return expect(subject, ...args);
      }
    }

    if (this.isFulfilled()) {
      return executeAnd();
    } else {
      return addAdditionalPromiseMethods(
        this.then(executeAnd),
        expect,
        subject
      );
    }
  };

  return promise;
}

module.exports = addAdditionalPromiseMethods;