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  5. 引用错(ReferenceError)

引用错(ReferenceError)

概述

引用错(ReferenceError) 对象代表当一个不存在的变量被引用时发生的错误。

语法

启 引用错([message[, fileName[, lineNumber]]])

参数

message
可选。描述可读的错误信息

fileName
 可选。包含引起异常代码的文件名

lineNumber
 可选。引起异常的代码行号

描述

当你尝试引用一个未被定义的变量时,将会抛出一个 ReferenceError 。

属性

ReferenceError.prototypeAllows the addition of properties to an ReferenceError object.

方法

全局的 ReferenceError 本身并不包含有方法,但是他可以从原型链上继承一些方法

ReferenceError 实例

属性

ReferenceError.prototype.constructor
Specifies the function that created an instance’s prototype.

信息 – ReferenceError.prototype.message
Error message. Although ECMA-262 specifies that ReferenceError should provide its own message property, in SpiderMonkey, it inherits Error.prototype.message.

名 – ReferenceError.prototype.name
Error name. Inherited from Error.

ReferenceError.prototype.fileName
Path to file that raised this error. Inherited from Error.

ReferenceError.prototype.lineNumber
Line number in file that raised this error. Inherited from Error.

ReferenceError.prototype.columnNumber
Column number in line that raised this error. Inherited from Error.

栈 – ReferenceError.prototype.stack
Stack trace. Inherited from Error.

方法

Although the ReferenceError prototype object does not contain any methods of its own, ReferenceError instances do inherit some methods through the prototype chain.

例子

例: 捕获一个 ReferenceError

try {
  var a = undefinedVariable;
} catch (e) {
  console.log(e instanceof ReferenceError); // true
  console.log(e.message);                   // "undefinedVariable is not defined"
  console.log(e.name);                      // "ReferenceError"
  console.log(e.fileName);                  // "Scratchpad/1"
  console.log(e.lineNumber);                // 2
  console.log(e.columnNumber);              // 6
  console.log(e.stack);                     // "@Scratchpad/2:2:7\n"
}

例: 创建一个 ReferenceError

try {
  throw new ReferenceError('Hello', 'someFile.js', 10);
} catch (e) {
  console.log(e instanceof ReferenceError); // true
  console.log(e.message);                   // "Hello"
  console.log(e.name);                      // "ReferenceError"
  console.log(e.fileName);                  // "someFile.js"
  console.log(e.lineNumber);                // 10
  console.log(e.columnNumber);              // 0
  console.log(e.stack);                     // "@Scratchpad/2:2:9\n"
}

原始MDN文档