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Javascript – What's the most efficient way to update an optional object property?

I have the following object. The data comes in from 2 separate messages, both of which have a timestamp and icao (id number). However, one message has ident info (callsign) and the other has aircraft position.

export interface AircraftInfo {
  timestamp: Date
  icao: string
  ident?: {
    callsign: string
  }
  pos?: {
    lat: number
    lon: number
    altitude: number
  }
}

As the data comes in, I update the necessary sections. What’s the most elegant way to update the pos property? I suspect if it already exists, the best thing to do is to update individual properties rather than overwriting with a new object. If it doesn’t, a new object has to be assigned.

This results in code like this:

  // update position if position exists, otherwise create position with position
  if (info.pos) {
    info.pos.altitude = altitude
    info.pos.lon = lon
    info.pos.lat = lat
  } else {
    info.pos = { altitude, lon, lat }
  }

This feels a little clunky. Is there a better way to do this?

Tags:

2

Answers


  1. 0

    I think this is less "clunky"

    if (!info.pos) info.pos = {};
info.pos.altitude = altitude;
info.pos.lon = lon;
info.pos.lat = lat;
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  2. 0

    I am not sure, but you may need a spread operator (this apprach brings immutability as well):

    https://stackblitz.com/edit/typescript-wbc2w2?file=index.ts

    interface AircraftInfo {
  timestamp: Date;
  icao: string;
  ident?: {
    callsign: string;
  };
  pos?: {
    lat: number;
    lon: number;
    altitude: number;
  };
}

const aircraftInfo: AircraftInfo = {
  timestamp: undefined,
  icao: '',
};

aircraftInfo.ident = {
  ...aircraftInfo.ident,
  callsign: 'callsign',
};

aircraftInfo.pos = {
  ...aircraftInfo.pos,
  lat: 1,
  lon: 2,
  altitude: 3,
};

console.log(aircraftInfo);
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