Ensuring the absence of values in deconstructed variables within an object

Question

Ensuring the absence of values in deconstructed variables within an object

In my quest to efficiently destructure the end_time property from the this.props.auction object, I encountered the code snippet below.

const {auction: {auction: {end_time}}} = this.props;

The problem with this code is that the constant will be undefined if the auction object is empty. To address this issue, I made a modification as follows:

if(Object.keys(this.props.auction).length) {
   var {auction: {auction: {end_time}}} = this.props;
} else {
   var {end_time} = "";
}

Although this solution works, it seems a bit convoluted, and I believe there must be a more elegant way to achieve the desired result.

After consulting a thread on Stack Overflow, I endeavored to simplify the code with the following attempt:

const {auction: {auction: {end_time = null}}} = this.props || {};

I initially thought that the above modification would default end_time to null in case the auction object is empty. However, it seems that the absence of the auction property is causing an error.

If you have a more efficient way to declare the end_time constant while handling an empty auction, I am eager to hear your suggestions.

javascript ecmascript-6

Answer 1

Answer №1

It is not mandatory to use destructuring whenever it is possible to do so.

const event = this.props.event.event;
const start_time = event === undefined ? null : event.start_time;

Answer 2

It is not mandatory to use destructuring whenever it is possible to do so.

const event = this.props.event.event;
const start_time = event === undefined ? null : event.start_time;

Answer 3

Answer №2

If you want to simplify the code and make it more readable, you can consider using the optional chaining operator and nullish coalescing operator like this:

const end_time = this.props?.auction?.auction?.end_time ?? null;

As Ry advised in a related discussion, it's not necessary to use destructuring in every situation where it is possible.

Even though this is related to ECMAScript 6, utilizing the optional chaining and nullish coalescing operators can make the code cleaner and more concise, especially once they are officially incorporated into the ECMAScript 2020 specification.

Answer 4

If you want to simplify the code and make it more readable, you can consider using the optional chaining operator and nullish coalescing operator like this:

const end_time = this.props?.auction?.auction?.end_time ?? null;

As Ry advised in a related discussion, it's not necessary to use destructuring in every situation where it is possible.

Even though this is related to ECMAScript 6, utilizing the optional chaining and nullish coalescing operators can make the code cleaner and more concise, especially once they are officially incorporated into the ECMAScript 2020 specification.

Answer 5

Answer №3

Utilizing the power of both Optional chaining and Nullish Coalescing Operator allows you to easily achieve this objective in a succinct manner with just a single line of code:

const end_time = props.auction?.auction?.end_time ?? '';

Check out some test functions below to grasp the concept:

const end_time_defaultValue = 'end_time_defaultValue';

function testWithEndTime() {
    const props = {
        auction: {
            auction: {
            end_time: new Date(),
            kay1: 'value1',
            kay2: 'value2'
            }
        }
    };
    const end_time = props.auction?.auction?.end_time ?? end_time_defaultValue;
    console.log('testWithEndTime() => ', end_time);
}
testWithEndTime();
// displays the current date

function testWithoutEndTime() {
    const props = {
    auction: {
        auction: {
        kay1: 'value1',
        kay2: 'value2'
        }
    }
    };
    const end_time = props.auction?.auction?.end_time ?? end_time_defaultValue;
    console.log('testWithoutEndTime() => ', end_time);
}
testWithoutEndTime();
// shows the end_time_defaultValue
// because the key 'end_time' is missing

function testWithoutAuctionAuction() {
    const props = {
        auction: {

        }
    };
    const end_time = props.auction?.auction?.end_time ?? end_time_defaultValue;
    console.log('testWithoutAuctionAuction() => ', end_time);
}
testWithoutAuctionAuction();
// displays the end_time_defaultValue
// because the key 'auction.auction' is not present

function testWithoutPropsAuction() {
    const props = {};;
    const end_time = props.auction?.auction?.end_time ?? end_time_defaultValue;
    console.log('testWithoutPropsAuction() => ', end_time);
}
testWithoutPropsAuction();
// shows the end_time_defaultValue
// because the key 'props.auction' does not exist

Take note of browser compatibility when implementing this technique

https://i.sstatic.net/p6Txc.png

If you're utilizing a framework like React, babel will handle this functionality for you.

Answer 6

Utilizing the power of both Optional chaining and Nullish Coalescing Operator allows you to easily achieve this objective in a succinct manner with just a single line of code:

const end_time = props.auction?.auction?.end_time ?? '';

Check out some test functions below to grasp the concept:

const end_time_defaultValue = 'end_time_defaultValue';

function testWithEndTime() {
    const props = {
        auction: {
            auction: {
            end_time: new Date(),
            kay1: 'value1',
            kay2: 'value2'
            }
        }
    };
    const end_time = props.auction?.auction?.end_time ?? end_time_defaultValue;
    console.log('testWithEndTime() => ', end_time);
}
testWithEndTime();
// displays the current date

function testWithoutEndTime() {
    const props = {
    auction: {
        auction: {
        kay1: 'value1',
        kay2: 'value2'
        }
    }
    };
    const end_time = props.auction?.auction?.end_time ?? end_time_defaultValue;
    console.log('testWithoutEndTime() => ', end_time);
}
testWithoutEndTime();
// shows the end_time_defaultValue
// because the key 'end_time' is missing

function testWithoutAuctionAuction() {
    const props = {
        auction: {

        }
    };
    const end_time = props.auction?.auction?.end_time ?? end_time_defaultValue;
    console.log('testWithoutAuctionAuction() => ', end_time);
}
testWithoutAuctionAuction();
// displays the end_time_defaultValue
// because the key 'auction.auction' is not present

function testWithoutPropsAuction() {
    const props = {};;
    const end_time = props.auction?.auction?.end_time ?? end_time_defaultValue;
    console.log('testWithoutPropsAuction() => ', end_time);
}
testWithoutPropsAuction();
// shows the end_time_defaultValue
// because the key 'props.auction' does not exist

Take note of browser compatibility when implementing this technique

https://i.sstatic.net/p6Txc.png

If you're utilizing a framework like React, babel will handle this functionality for you.

Answer 7

Answer №4

To improve readability and avoid potential issues, consider de-structuring in 2 separate steps. First, de-structure your props, then access the necessary object which may be undefined at certain points during the component's life cycle.

// Instead of
const {auction: {auction: {end_time}}} = this.props;

// You can do
const { auction } = this.props;
let end_time;
if(auction){
   ({ end_time } = auction);
}

Answer 8

To improve readability and avoid potential issues, consider de-structuring in 2 separate steps. First, de-structure your props, then access the necessary object which may be undefined at certain points during the component's life cycle.

// Instead of
const {auction: {auction: {end_time}}} = this.props;

// You can do
const { auction } = this.props;
let end_time;
if(auction){
   ({ end_time } = auction);
}

Ensuring the absence of values in deconstructed variables within an object

Answer №1

Answer №2

Answer №3

Answer №4

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