为什么我们明确提到要开玩笑地测试环境属性?

I was going through jest configuration docs and other tutorials for setting up Jest, they have one thing common which is

  module.exports = {
  testEnvironment: "node",
};

有人可以向我解释为什么我们需要此属性,它的用途是什么,它如何影响玩笑功能?