为什么此代码显示错误？

Question

The 2nd line is showing error.

"ReferenceError: specialTrick is not defined
    at CoolGuy.showoff (<anonymous>:23:40)
    at <anonymous>:31:5
    at Object.InjectedScript._evaluateOn (<anonymous>:875:140)
    at Object.InjectedScript._evaluateAndWrap (<anonymous>:808:34)
    at Object.InjectedScript.evaluate (<anonymous>:664:21)"

 class CoolGuy { specialTrick = null; CoolGuy( trick ) { specialTrick = trick } showOff() { console.log( "Here's my trick: ", specialTrick ); } } Joe = new CoolGuy("rope climbing"); Joe.shoeOff(); 

Answer 1

1. You should use the constructor function (and not a function with the same name).
2. You can't set members inside the class definition (you set them inside the constructor), using this .
3. You had a typo in the showOff function.

More information in the reference .

Here is the fix:

 class CoolGuy { constructor( trick ) { this.specialTrick = trick } showOff() { console.log( "Here's my trick: ", this.specialTrick ); } } Joe = new CoolGuy("rope climbing"); Joe.showOff();