What is preventing TypeScript from recognizing the key property as a component of the Event type?

Question

What is preventing TypeScript from recognizing the key property as a component of the Event type?

After creating a function that uses events to determine which button a user pressed by utilizing the event.key property, I encountered an issue. When assigning a type Event as a parameter for the function, the compiler generates an error message stating that

Property 'key' does not exist on type 'Event'.

Below is my code snippet:

function getDirection(e:Event):void{
    let directionCode:number = e.key; 
    // add more code here
}

I'm puzzled as to why the key property isn't recognized in this instance of the event type.

typescript events types

Answer 1

Answer №1

Since the Event object lacks that specific property, it is advisable to utilize the KeyboardEvent class instead.

function determineDirection(e:KeyboardEvent):void{
    let directionCode:number = e.keyCode; 
    let directionCodeStr:string = e.key; 
    // additional code here
}

Answer 2

Since the Event object lacks that specific property, it is advisable to utilize the KeyboardEvent class instead.

function determineDirection(e:KeyboardEvent):void{
    let directionCode:number = e.keyCode; 
    let directionCodeStr:string = e.key; 
    // additional code here
}

Answer 3

Answer №2

It is recommended to properly typecast your event listener:

myInput.addEventListener('keyup', (e) => {
    let keyboardEvent = <KeyboardEvent> e;
    if(keyboardEvent.keyCode === 40){
        //...
    }
}

In addition, since event.keyCode is deprecated, you can use the following method:

myInput.addEventListener('keyup', (e) => {
    let keyboardEvent = <KeyboardEvent> e;
    if(keyboardEvent.key === 'ArrowDown'){
        //...
    }
}

Answer 4

It is recommended to properly typecast your event listener:

myInput.addEventListener('keyup', (e) => {
    let keyboardEvent = <KeyboardEvent> e;
    if(keyboardEvent.keyCode === 40){
        //...
    }
}

In addition, since event.keyCode is deprecated, you can use the following method:

myInput.addEventListener('keyup', (e) => {
    let keyboardEvent = <KeyboardEvent> e;
    if(keyboardEvent.key === 'ArrowDown'){
        //...
    }
}

What is preventing TypeScript from recognizing the key property as a component of the Event type?

Answer №1

Answer №2

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