Nullish coalescing testing for undefined-CodePudding

ive got this function that calls an API

interface getEventsPropsShape {
    eventId?: string;
    accountId?: string;
    eventsStartAfter?: string;
  }

  const getEvents = async ({
    eventId,
    accountId,
    eventsStartAfter,
  }: getEventsPropsShape): Promise<void> => {
    let apiUrl: string = '/v1/developer/events?limit=25&ascending=false';
    eventId !== undefined ?? (apiUrl  = `&eventId=${eventId}`);
    accountId !== undefined ?? (apiUrl  = `&accountId=${accountId}`);
    eventsStartAfter !== undefined ??
      (apiUrl  = `&eventsStartAfter=${eventsStartAfter}`);
    const response = await get(apiUrl);

This works because it doesn't add eventId to apiUrl

let apiUrl: string = '/v1/developer/events?limit=25&ascending=false';
eventId !== undefined ?? (apiUrl  = `&eventId=${eventId}`);

but this doesn't work because it ads eventId = undefined to the apiUrl

let apiUrl: string = '/v1/developer/events?limit=25&ascending=false';
eventId ?? (apiUrl  = `&eventId=${eventId}`);

ultimately I'm looking to remove the if blocks from

    if (eventId) apiUrl  = `&eventId=${eventId}`;
    if (accountId) apiUrl  = `&accountId=${accountId}`;
    if (eventsStartAfter) apiUrl  = `&eventsStartAfter=${eventsStartAfter}`;

CodePudding user response：

Change ?? to &&. Example:

let eventId = undefined;
let apiUrl = '/v1/developer/events?limit=25&ascending=false';

eventId && (apiUrl  = `&eventId=${eventId}`);
console.log(apiUrl);

eventId = 'foo';
apiUrl = '/v1/developer/events?limit=25&ascending=false';
eventId && (apiUrl  = `&eventId=${eventId}`);
console.log(apiUrl);

Or:

let eventId = null;
let apiUrl = '/v1/developer/events?limit=25&ascending=false';

eventId !== undefined && (apiUrl  = `&eventId=${eventId}`);
console.log(apiUrl);

eventId = 'foo';
apiUrl = '/v1/developer/events?limit=25&ascending=false';
eventId !== undefined && (apiUrl  = `&eventId=${eventId}`);
console.log(apiUrl);