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optional chaining in js

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Fahad Shaikh answered on February 25, 2020 Popularity 10/10 Helpfulness 3/10

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// Optional chaining

// Basically Optional chaining is use nested destructuring like shown below !!

// const obj = [{
//  obj: {
//   obj: "FAhad",
//  },
//}]

// console.log(obj[0]?.obj?.obj);

// Like as you watched that How we are getting the elements from obj

const obj = [{
  obj: {
  },
}]

console.log(obj[0]?.obj?.obj);

// It's retruning undefined just because of optional chaining otherwise it'll return an error 

// ----------THE END----------

Popularity 10/10 Helpfulness 3/10 Language javascript

Source: Grepper

Tags: javascript optional-chaining

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Contributed on Sep 24 2022

Fahad Shaikh

0 Answers Avg Quality 2/10

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js optional chaining array

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// For arrays
const friendAtPositionZeroIfItExists = user?.friends?.[0]

Popularity 9/10 Helpfulness 3/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on Sep 13 2022

FelDev

0 Answers Avg Quality 2/10

optional chain operator

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const adventurer = {
  name: 'Alice',
  cat: {
    name: 'Dinah'
  }
};

const dogName = adventurer.dog?.name;
console.log(dogName);
// expected output: undefined

Popularity 10/10 Helpfulness 3/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on Oct 12 2020

Lokesh003

0 Answers Avg Quality 2/10

optional chaining

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let myMap = new Map();
myMap.set("foo", {name: "baz", desc: "inga"});

let nameBar = myMap.get("bar")?.name;

Popularity 10/10 Helpfulness 3/10 Language javascript

Source: developer.mozilla.org

Tags: javascript j

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Contributed on Feb 25 2020

Angry Aardvark

0 Answers Avg Quality 2/10

Optional Chaining javascript

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The optional chaining operator provides a way to simplify accessing values through connected objects when it's possible that a reference or function may be undefined or null.

For example, consider an object obj which has a nested structure. Without optional chaining, looking up a deeply-nested subproperty requires validating the references in between, such as:

let nestedProp = obj.first && obj.first.second;
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The value of obj.first is confirmed to be non-null (and non-undefined) before then accessing the value of obj.first.second. This prevents the error that would occur if you accessed obj.first.second directly without testing obj.first.

With the optional chaining operator (?.), however, you don't have to explicitly test and short-circuit based on the state of obj.first before trying to access obj.first.second:

let nestedProp = obj.first?.second;
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By using the ?. operator instead of just ., JavaScript knows to implicitly check to be sure obj.first is not null or undefined before attempting to access obj.first.second. If obj.first is null or undefined, the expression automatically short-circuits, returning undefined.

This is equivalent to the following, except that the temporary variable is in fact not created:

let temp = obj.first;
let nestedProp = ((temp === null || temp === undefined) ? undefined : temp.second);

Popularity 10/10 Helpfulness 2/10 Language javascript

Source: developer.mozilla.org

Tags: javascript j

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Contributed on Apr 23 2022

khal

0 Answers Avg Quality 2/10

Optional chaining

Comment

let x = foo?.bar();

if (foo?.bar?.baz) { // ... }

Popularity 10/10 Helpfulness 2/10 Language typescript

Source: stackoverflow.com

Tags: optional-chaining optional-chainin

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Contributed on Jun 04 2021

Blushing Bug

0 Answers Avg Quality 2/10

optional-chaining operator

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if (user?.team?.subscription?.invoices) {
  //
}

Popularity 10/10 Helpfulness 1/10 Language javascript

Source: dev.to

Tags: javascript j

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Contributed on Jan 06 2021

Mystic Dev

0 Answers Avg Quality 2/10

optional chaining

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const greeting = object?.deepProp?.deeperProp?.greet

Popularity 10/10 Helpfulness 1/10 Language javascript

Source: swizec.com

Tags: javascript j

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Contributed on Jun 25 2021

Jaimin Patel

0 Answers Avg Quality 2/10

optional chaining in javascript

Comment

method1?.method2.method3

Popularity 10/10 Helpfulness 1/10 Language javascript

Source: Grepper

Tags: javascript j

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Contributed on Feb 22 2022

Ashu Chaudhary

0 Answers Avg Quality 2/10

optional chaining

Comment

/* 
* optional chaining (?.) allows me to write code that stops 
* running when we encounter a null or undefined value
*/

function tryGetFirstElement<T>(arr?: T[]) {
    return arr?.[0];
    // equivalent to
    //   return (arr === null || arr === undefined) ?
    //       undefined :
    //       arr[0];
}

Popularity 10/10 Helpfulness 1/10 Language typescript

Source: www.typescriptlang.org

Tags: optional-chaining optional-chainin

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Contributed on Mar 02 2020

Impossible Impala

0 Answers Avg Quality 2/10

optional chaining in js

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