Attempting to call upon an object that may be undefined is not possible

Here is the code snippet that I am working with:

  dispatchEvent(name: TableEventName, params: any): any {
    const event =
      typeof this.options?.event?.[name] === 'function' ? this.options.event[name] : () => {}
    return event(params)
  }

When I compile it, I get the error message:

Cannot invoke an object which is possibly 'undefined'. return event(params)

I have gone through and checked my conditionals, so why is this error occurring?

Below is the full code for reference:


type TableEventName = 'onStateChange' | 'onSort' | 'onPageChange' | 'onSelection'

interface TableOptions {
  event?: {
    onStateChange?: (event: any) => void
    onSort?: (event: any) => void
    onPageChange?: (event: any) => void
    onSelection?: (event: any) => void
  }
}

let options: TableOptions = {
    event: {
        onSort: () => { } 
    }
}

let dispatcher = function (name: TableEventName, params: any): any {
    const event =
      typeof options?.event?.[name] === 'function' ? options.event[name] : () => {}
    return event(params)
}

here

Answer №1

One way to utilize optional chaining is by following this example:

const handleEvent = function (name: EventType, data: any): any {
  const action = config.event?.[name];
  
  return action?.(data);
}

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