[Question] How to delete a header in a custom function

[ttttmr]

The value of header set to _header_editor_remove_ doesn't seem to work.

I tried to use delete val[i], but the browser threw an error

for(let i=0;i<val.length;i++){
    if(xx){
        delete val[i]
    }
}

Error in event handler: TypeError: Error in invocation of webRequestInternal.eventHandled(string eventName, string subEventName, string requestId, integer webViewInstanceId, optional webRequest.BlockingResponse response): Error at parameter 'response': Error at property 'requestHeaders': Error at index 9: Invalid type: expected object, found undefined.
    at subEventCallback (extensions::webRequestEvent:107:28)