类：ReferenceError

¥Class: ReferenceError

• 继承：<errors.Error>

  ¥Extends: <errors.Error>

表示正在尝试访问未定义的变量。此类错误通常表示代码中存在拼写错误或程序损坏。

¥Indicates that an attempt is being made to access a variable that is not defined. Such errors commonly indicate typos in code, or an otherwise broken program.

虽然客户端代码可能会产生和传播这些错误，但实际上只有 V8 会这样做。

¥While client code may generate and propagate these errors, in practice, only V8 will do so.

doesNotExist;
// Throws ReferenceError, doesNotExist is not a variable in this program. 拷贝

除非应用动态生成和运行代码，否则 ReferenceError 实例表明代码或其依赖中存在错误。

¥Unless an application is dynamically generating and running code, ReferenceError instances indicate a bug in the code or its dependencies.