DEV Community

Cover image for You MUST store this Javascript Operator Index
Code Oz
Code Oz

Posted on • Updated on

You MUST store this Javascript Operator Index

Here is a list of javascript operator and how to use it!

You should mark this and use it when you need to know what is this operator!

In order to naviguate, you can make a cmd + f or ctrl + f and put the operator that you need and put : after this.

Example: ...: if I'm looking for what is ... operator

🚨 Popularity is defined by my OWN usage.

Ambidextrous operator

+: addition | unary plus

Popularity: ★★★★☆

If you use + operator BEFORE operand, it will be used as unary plus operator.

The unary plus operator precedes its operand and evaluates to its operand but attempts to convert it into a number, if it isn't already.

const x = 1
const y = -1

console.log(+x)
// expected output: 1

console.log(+y)
// expected output: -1

console.log(+'')
// expected output: 0

console.log(+true)
// expected output: 1

console.log(+false)
// expected output: 0

console.log(+'hello')
// expected output: NaN
Enter fullscreen mode Exit fullscreen mode

📝 Note: If you try to use it with a string that is not a number, it will return NaN (not a number)

If you use + operator in other context will be used as addition operator.

It Produces the sum of numeric operands except for string

📝 Note: It will convert boolean to number, object to number

console.log(2 + 4) // 6
console.log(2 + true) // 3
Enter fullscreen mode Exit fullscreen mode

When you use it with string it will make a string concatenation

const name = 'code oz'
console.log('hello ' + 'my name is ' + name)
Enter fullscreen mode Exit fullscreen mode

📝 Note: you should use template litterals string instead of concatenation

-: subtraction | unary negation

Popularity: ★★★★☆

If you use - operator BEFORE operand, it will be used as unary negation operator.

The unary negation operator precedes its operand and negates it.

📝 Note: It will convert boolean to number, object to number & string to number

const a = 5
console.log(-a) // -5
console.log(-'1') // -1
Enter fullscreen mode Exit fullscreen mode

📝 Note: If you try to use it with a string that is not a number, it will return NaN (not a number)

If you use - operator in other context will be used as subtraction operator.

It subtracts the two operands, producing their difference.

console.log(5 - 3)
// expected output: 2

console.log(3.5 - 5)
// expected output: -1.5

console.log(5 - 'hello')
// expected output: NaN

console.log(5 - true)
// expected output: 4
Enter fullscreen mode Exit fullscreen mode

...: spread | rest

Popularity: ★★★★☆

If you use ... operator as function argument during execution, it will turns array into a list of arguments. In this context it's called Spread operator.

let arr = [3, 5, 1]

Math.max(...arr) // 5 (spread turns array into a list of arguments)
Enter fullscreen mode Exit fullscreen mode

You can use ... operator in another way that is the opposite of turning array into a list, it's when you convert some item into an array!

It allows us to have an unlimited number of parameter for this function! since it will convert the arguments (list of item) into an array that is the argument!

// rest parameter is handle as array in the function
const add = (...rest) => {
   return rest.reduce((total, current) => total + current)
}

// Nice your function can handle different number of parameters !
add(1, 2, 3)
add(1, 2, 3, 4, 5)
Enter fullscreen mode Exit fullscreen mode

You can also use it for extracting values from array or object

// We extract the first Item of the array into the variable and the others variable in an array named others
const [ firstItem, ...others ] = [ 1, 2, 3, 4 ]
firstItem // 1
others // [ 2, 3, 4 ]
Enter fullscreen mode Exit fullscreen mode
const toto = { a: 1, b: 2, c: 3 }
const { a, ...others } = toto
a // 1, we extract the a key from toto object
others // { b: 2, c: 3 }, we extract other key in the object thanks to rest operator 
Enter fullscreen mode Exit fullscreen mode

📝 Note: When you are doing const toto = { ...anotherObject } it's equal to const toto = Object.assign({}, anotherObject)

Summarize:

Spread operator: Transform arrays into list of arguments.

Rest operator: Transform list of arguments into an array.

Logical operator

Thing to know: All value in Javascript are falsy or truthy value, it means that you can make Boolean(any value), and you will get boolean value. In Javascript all value are truthy value except 0, null, undefined, NaN, empty string

&&: logical AND

Popularity: ★★★★★

Use to check if all value (in general value are condition) are truthy.

It will return the first value falsy, otherwise it will return the final value.

const isTrue = true
const isFalse = false


const value = isFalse && isTrue // will return false 
const valueBis = isTrue && isFalse // will return false

const toto = 5 && 3 && 1 // will return 1 since all value before are true (5 & 3)

const tutu = 5 && 0 && 2 // will return 0 since it's the first falsy value

if (firstCondition && secondCondition) { console.log('hello') } // console log will be shown only if both condition are true!
Enter fullscreen mode Exit fullscreen mode

&&=: logical AND assignement

Popularity: ★☆☆☆☆

Value is assigned only if value passed is truthy.

let toto = 0
let tutu = 2

toto &&= 5 // toto value will be NOT changed since toto is falsy (0)
tutu &&= 3 // tutu value will be replaced by 3 since tutu is trusly (2)

// toto &&= 5 It's a shortcut of 👇

let toto = 0 

toto = toto && 5
Enter fullscreen mode Exit fullscreen mode

||: logical OR

Popularity: ★★★★☆

Use to check if one value (in general value are condition) are truthy among a set of value.

It will return the first value truthy, otherwise it will return the final value.

const isTrue = true
const isFalse = false

const value = isFalse || isTrue // will return true 
const valueBis = isTrue || isFalse // will return true

const toto = 5 || 3 || 1 // will return 5 since it's the first truthy value

const tutu = 0 || 2 || 5 // will return 2 since it's the first truthy value

if (firstCondition || secondCondition) { console.log('hello') } // console log will be shown if one condition matches!
Enter fullscreen mode Exit fullscreen mode

||=: logical OR assignement

Popularity: ★☆☆☆☆

Value is assigned only if value passed is falsy.

let toto = 0
let tutu = 2

toto ||= 5 // toto value will be replaced by 5 since toto is falsy (0)
tutu ||= 3 // tutu value will NOT changed since tutu is not a falsy value (2)

// toto ||= 5 It's a shortcut of 👇

let toto = 0 

toto = toto || 5
Enter fullscreen mode Exit fullscreen mode

??: logical Nullish Coalescing

Popularity: ★★★☆☆

Returns its its right-hand side operand when its left-hand side operand is null or undefined (nullish value).

const toto = 0 ?? 55 // 0 since 0 is not equal to nullish value.
const tutu = null ?? 'hello' // 'hello' since the right-hand side is equal to `null`
const tata = undefined ?? 55 // '55 since the right-hand side is equal to `undefined`
const titi = null ?? undefined // undefined since the right-hand side is equal to `null`
Enter fullscreen mode Exit fullscreen mode

⚠️ Be careful: ?? operator is different of ||, so when you need to assign a value depending on other value, you should pick the correct operator!

const toto = 0 || 55 // 55 since 0 is a falsy value
const titi = 0 ?? 55 // 0 since 0 is different of nullish value

const tutu = undefined || 55 // 55 since undefined is a falsy value
const tata = undefined ?? 55 // 55 since undefined is equal to nullish value
Enter fullscreen mode Exit fullscreen mode

??=: logical Nullish assignement

Popularity: ★☆☆☆☆

Value is assigned only if value passed is equal to null or undefined (nullish).

let toto = null
toto ??= 55 // toto is equal to 55 since it's a nullish value (null)

let tutu = 90
tutu ??= 23 // toto is equal to 90 since it's not a nullish value (90)
// toto ??= 5 It's a shortcut of 👇

let toto = null

toto = toto ?? 5 // Equal to 5 since toto is equal to null
Enter fullscreen mode Exit fullscreen mode

!: logical NOT

Popularity: ★★★★★

Swap a true value into false value and false value into true value.

It also convert any value to boolean value. So all truthy value become falsy value and vice versa.

💡 Tips: I use double logical operator a lot in order to convert any value to boolean! It's equal to use Boolean(any value)

console.log(!true) // false
console.log(!true) // true
console.log(!0) // false
console.log(!1) // true

console.log(!{}) // false
console.log(![]) // false
console.log(!undefined) // true

// My tips 👇
console.log(!!{}) // true, equal to Boolean({})
console.log(!![]) // true, equal to Boolean([])

if (!!value) { ... } // I use a lot in order to check if a value is defined or undefined! (Be careful, if the value is equal to `0` it will be false!)
Enter fullscreen mode Exit fullscreen mode

Special operator

?.: Optional chaining

Popularity: ★★★★☆

It allows to accesses a property on an object without having to check if each reference in the chain is valid.

It's not really clear? Ok let's have a look 👇

const toto = { a: { b: 5 } }
toto.a // { b: 5 }
toto.a.b // 5
toto.a.b.c // undefined
toto.a.b.c.d // Uncaught TypeError: Cannot read properties of undefined
Enter fullscreen mode Exit fullscreen mode

In fact in you try to access to a property on an undefined property, Javascript engine will trigger an error!

So to be safe we need to make something like 👇

const toto = { a: { b: 5 } }

if (toto.a && toto.a.b && toto.a.b.c && toto.a.b.c.d) {
    console.log(toto.a.b.c.d) // It's safe to use it since we check before if the property exist!
}
Enter fullscreen mode Exit fullscreen mode

But it's not really convenient to make this, isn't?

So opional chaining is here to save us! 🦸‍♂️

You can try to access to a property without check if all property exist before as show above! You just need to use this operator on property, if the property doesn't exist, it will return undefined.

const toto = { a: { b: 5 } }
toto?.a?.b // 5
toto?.a?.b?.c?.d // undefined
Enter fullscreen mode Exit fullscreen mode

?: Ternary

Popularity: ★★★★☆

Is the only operator in Javascript that requires two pseudo operand (? and :). It evaluate a condition depending on whether that condition is falsy or truthy! It's equivalent to if (...) & else (...).

console.log(true ? 55 : 10) // 55
console.log(0 ? 13 : 34) // 34

const toto = 2 > 1
console.log(toto ? 'ok' : 'not ok')

//  It's a shortcut of 👇

if (toto) {
    console.log('ok')
} else {
    console.log('not ok')
}
Enter fullscreen mode Exit fullscreen mode

Comparator operator

==: Equality

Popularity: ★☆☆☆☆

It checks whether its two operands are equal, returning a Boolean result. Unlike the === (strict equality operator), it attempts to convert (make an implicit coercion) and compare operands that are of different types.

📝 Note: The mechanic of implicit coercion is not easy to understand but you can check it in details at this post https://dev.to/codeozz/implicit-coercion-in-javascript-neh

Here an exemple of how the implicit corecion is done! 👇

// 1) Not the same type so implicit coercion will be made
'24' == 24

// 2) Convert string into number so 
Number('24') == 24

// 3) We got an number so we can check value
24 == 24 // true !
Enter fullscreen mode Exit fullscreen mode

In general you should use === (strict equality) and avoid this operator!

===: Strict Equality

Popularity: ★★★★★

It checks whether its two operands are equal, returning a Boolean result. Unlike the == (equality operator), the strict equality operator always considers operands of different types to be different.

console.log(1 === 1)
// expected output: true

console.log('hello' === 'hello')
// expected output: true

console.log('1' ===  1)
// expected output: false

console.log(0 === false)
// expected output: false
Enter fullscreen mode Exit fullscreen mode

You should always use this operator instead of == (equality operator)!

!=: Inequality

Popularity: ★☆☆☆☆

It checks whether its two operands are not equal, returning a Boolean result. Unlike the !== (strict inequality operator), it attempts to convert and compare operands that are of different types.

console.log(1 != 1)
// expected output: false

console.log('hello' != 'hello')
// expected output: false

console.log('1' !=  1)
// expected output: false

console.log(0 != false)
// expected output: false
Enter fullscreen mode Exit fullscreen mode

In general you should use !== (strict inequality) and avoid this operator!

!==: Strict Inequality

Popularity: ★★★★★

It checks whether its two operands are not equal, returning a Boolean result. Unlike the (!= inequality operator), the strict inequality operator always considers operands of different types to be different.

console.log(1 !== 1)
// expected output: false

console.log('hello' !== 'hello')
// expected output: false

console.log('1' !==  1)
// expected output: true

console.log(0 !== false)
// expected output: true
Enter fullscreen mode Exit fullscreen mode

You should always use this operator instead of != (inequality)!

>: Greater than

Popularity: ★★★★☆

It returns true if the left operand is greater than the right operand, and false otherwise.

console.log(5 > 3)
// expected output: true

console.log(3 > 3)
// expected output: false

console.log('ab' > 'aa')
// expected output: true
Enter fullscreen mode Exit fullscreen mode

>=: Greater than or Equal To

Popularity: ★★★★☆

It returns true if the left operand is greater than or equal to the right operand, and false otherwise.

console.log(5 >= 3)
// expected output: true

console.log(3 >= 3)
// expected output: true

console.log('ab' >= 'aa')
// expected output: true
Enter fullscreen mode Exit fullscreen mode

<: Less than

Popularity: ★★★★☆

It returns true if the left operand is less than the right operand, and false otherwise.

console.log(5 < 3)
// expected output: false

console.log(3 < 3)
// expected output: false

console.log('aa' < 'ab')
// expected output: true
Enter fullscreen mode Exit fullscreen mode

<=: Less than or Equal To

Popularity: ★★★★☆

It returns true if the left operand is less than or equal to the right operand, and false otherwise.

console.log(5 <= 3)
// expected output: false

console.log(3 <= 3)
// expected output: true

// Compare bigint to number (note: bigint is not supported in all browsers)
console.log(3n <= 5)
// expected output: true

console.log('aa' <= 'ab')
// expected output: true
Enter fullscreen mode Exit fullscreen mode

Arithmetic operator

+=: Addition Assignment

Popularity: ★★★☆☆

Adds the value of the right operand to a variable and assigns the result to the variable.

let a = 5
let b = 3

b += a // b will be equal to 8, since we are adding 5 to b variable!
Enter fullscreen mode Exit fullscreen mode

-=: Subtraction Assignment

Popularity: ★★★☆☆

Subtracts the value of the right operand to a variable and assigns the result to the variable.

let a = 5
let b = 3

b -= a // b will be equal to 2, since we are subtracting 5 to b variable!
Enter fullscreen mode Exit fullscreen mode

*: Multiplication

Popularity: ★★★☆☆

Its produces the product of the operands.

let a = 5
let b = 3

let c = a * b // 15
Enter fullscreen mode Exit fullscreen mode

*=: Multiplication Assignment

Popularity: ★★★☆☆

Multiple the value of the right operand to a variable and assigns the result to the variable.

let a = 5
let b = 3

b *= a // 15
Enter fullscreen mode Exit fullscreen mode

/: Division

Popularity: ★★★☆☆

Its produces the quotient of its operands where the left operand is the dividend and the right operand is the divisor.

let a = 10
let b = 2

let c = a / b // 2

console.log(1 / 0) // Infinity
Enter fullscreen mode Exit fullscreen mode

/=: Division Assignment

Popularity: ★★★☆☆

Divide the value of the right operand to a variable and assigns the result to the variable.

let a = 10
let b = 2

b /= a // 2
Enter fullscreen mode Exit fullscreen mode

**: Exponentiation

Popularity: ★★★☆☆

Its returns the result of raising the first operand to the power of the second operand. It is equivalent to Math.pow, except it also accepts BigInts as operands.

let a = 10
let b = 2

let c = a ** b // 100, it equals to 10^2 or Math.pow(10, 2)
Enter fullscreen mode Exit fullscreen mode

**=: Exponentiation Assignment

Popularity: ★★★☆☆

It raises the value of a variable to the power of the right operand.

let a = 10
let b = 2

b **= a // 1024, it equals to 2^10 or Math.pow(2, 10)
a **= b // 100, it equals to 10^2 or Math.pow(10, 2)
Enter fullscreen mode Exit fullscreen mode

%: Remainder (modulo)

Popularity: ★☆☆☆☆

Its returns the remainder left over when one operand is divided by a second operand. It always takes the sign of the dividend.

let a = 10
let b = 3

let c = a % b // 1
Enter fullscreen mode Exit fullscreen mode

More information about modulo in mathematic -> https://simple.wikipedia.org/wiki/Modulo_operation

%=: Remainder Assignment

Popularity: ★☆☆☆☆

It divides a variable by the value of the right operand and assigns the remainder to the variable.

let a = 10
let b = 3

a %= b // 1 it's equal to a % b
Enter fullscreen mode Exit fullscreen mode

More information about modulo in mathematic -> https://simple.wikipedia.org/wiki/Modulo_operation

++: Increment

Popularity: ★★★☆☆

It increments (adds one to) its operand and returns a value.

You can use it in two ways:

  • As pre increment: It increment the value before the operation
let toto = 55

console.log(toto) // 55
console.log(++toto) // 56
console.log(toto) // 56
Enter fullscreen mode Exit fullscreen mode
  • As post increment: It increment the value after the operation
let toto = 55

console.log(toto) // 55
console.log(toto++) // 55
console.log(toto) // 56
Enter fullscreen mode Exit fullscreen mode

--: Decrement

Popularity: ★★★☆☆

It decrement (subtracts one to) its operand and returns a value.

You can use it in two ways:

  • As pre decrement: It decrement the value before the operation
let toto = 55

console.log(toto) // 55
console.log(--toto) // 54
console.log(toto) // 54
Enter fullscreen mode Exit fullscreen mode
  • As post decrement: It decrement the value after the operation
let toto = 55

console.log(toto) // 55
console.log(toto--) // 55
console.log(toto) // 54
Enter fullscreen mode Exit fullscreen mode

Bits operator

&: Bitwise AND

Popularity: ★☆☆☆☆

Returns a 1 in each bit position for which the corresponding bits of both operands are 1s.

⚠️ Be careful: Don't be confused between & and && operator! The && is the logical operator AND

const a = 5        // 00000000000000000000000000000101
const b = 3        // 00000000000000000000000000000011

console.log(a & b) // 00000000000000000000000000000001
Enter fullscreen mode Exit fullscreen mode

💡 Tips: If you need to check if a number is even, you can use numberVar & 1, if the result is equal to 0, your number is even!

&=: Bitwise AND assignment

Popularity: ★☆☆☆☆

It uses the binary representation of both operands, does a bitwise AND operation on them and assigns the result to the variable.

let a = 5      // 00000000000000000000000000000101
a &= 3         // 00000000000000000000000000000011

console.log(a) // 00000000000000000000000000000001
Enter fullscreen mode Exit fullscreen mode

~: Bitwise NOT

Popularity: ★☆☆☆☆

It inverts the bits of its operand. Like other bitwise operators, it converts the operand to a 32-bit signed integer

const a = 5     // 00000000000000000000000000000101
const b = -3    // 11111111111111111111111111111101

console.log(~a) // 11111111111111111111111111111010
// expected output: -6

console.log(~b) // 00000000000000000000000000000010
// expected output: 2
Enter fullscreen mode Exit fullscreen mode

|: Bitwise OR

Popularity: ★☆☆☆☆

It returns a 1 in each bit position for which the corresponding bits of either or both operands are 1s.

const a = 5        // 00000000000000000000000000000101
const b = 3        // 00000000000000000000000000000011

console.log(a | b) // 00000000000000000000000000000111
// expected output: 7
Enter fullscreen mode Exit fullscreen mode

|=: Bitwise OR assignment

Popularity: ★☆☆☆☆

It uses the binary representation of both operands, does a bitwise OR operation on them and assigns the result to the variable.

let a = 5      // 00000000000000000000000000000101
a |= 3         // 00000000000000000000000000000011

console.log(a) // 00000000000000000000000000000111
// expected output: 7
Enter fullscreen mode Exit fullscreen mode

^: Bitwise XOR

Popularity: ★☆☆☆☆

It returns a 1 in each bit position for which the corresponding bits of either but not both operands are 1s.

const a = 5        // 00000000000000000000000000000101
const b = 3        // 00000000000000000000000000000011

console.log(a ^ b) // 00000000000000000000000000000110
Enter fullscreen mode Exit fullscreen mode

^=: Bitwise XOR assignment

Popularity: ★☆☆☆☆

It uses the binary representation of both operands, does a bitwise XOR operation on them and assigns the result to the variable.

let a = 5      // 00000000000000000000000000000101
a ^= 3         // 00000000000000000000000000000011

console.log(a) // 00000000000000000000000000000110
// expected output: 6
Enter fullscreen mode Exit fullscreen mode

<<: Left shift

Popularity: ★☆☆☆☆

Shifts the first operand the specified number of bits to the left. Excess bits shifted off to the left are discarded. Zero bits are shifted in from the right.

const a = 5         // 00000000000000000000000000000101
const b = 2         // 00000000000000000000000000000010

console.log(a << b) // 00000000000000000000000000010100
// expected output: 20
Enter fullscreen mode Exit fullscreen mode

<<=: Left shift assignment

Popularity: ★☆☆☆☆

Moves the specified amount of bits to the left and assigns the result to the variable.

let a = 5 // 00000000000000000000000000000101

a <<= 2   // 00000000000000000000000000010100

console.log(a)
// expected output: 20
Enter fullscreen mode Exit fullscreen mode

>>: Right shift

Popularity: ★☆☆☆☆

Shifts the first operand the specified number of bits to the right. Excess bits shifted off to the right are discarded. Copies of the leftmost bit are shifted in from the left.

Since the new leftmost bit has the same value as the previous leftmost bit, the sign bit (the leftmost bit) does not change. Hence the name "sign-propagating".

const a = 5          //  00000000000000000000000000000101
const b = 2          //  00000000000000000000000000000010
const c = -5         // -00000000000000000000000000000101

console.log(a >> b)  //  00000000000000000000000000000001
// expected output: 1

console.log(c >> b)  // -00000000000000000000000000000010
// expected output: -2
Enter fullscreen mode Exit fullscreen mode

>>=: Right shift assignment

Popularity: ★☆☆☆☆

Moves the specified amount of bits to the right and assigns the result to the variable.

let a = 5      //  00000000000000000000000000000101

a >>= 2        //  00000000000000000000000000000001
console.log(a)
// expected output: 1

let b = -5     // -00000000000000000000000000000101

b >>= 2        // -00000000000000000000000000000010
console.log(b)
// expected output: -2
Enter fullscreen mode Exit fullscreen mode

>>>: Unsigned Right shift

Popularity: ★☆☆☆☆

Shifts the first operand the specified number of bits to the right. Excess bits shifted off to the right are discarded.

Zero bits are shifted in from the left.

The sign bit becomes 0, so the result is always non-negative. Unlike the other bitwise operators, zero-fill right shift returns an unsigned 32-bit integer.

const a = 5          //  00000000000000000000000000000101
const b = 2          //  00000000000000000000000000000010
const c = -5         // -00000000000000000000000000000101

console.log(a >>> b) //  00000000000000000000000000000001
// expected output: 1

console.log(c >>> b) //  00111111111111111111111111111110
// expected output: 1073741822
Enter fullscreen mode Exit fullscreen mode

>>>=: Unsigned Right shift assignment

Popularity: ★☆☆☆☆

Moves the specified amount of bits to the right and assigns the result to the variable.

let a = 5 //  00000000000000000000000000000101

a >>>= 2  //  00000000000000000000000000000001
console.log(a)
// expected output: 1

let b = -5 // -00000000000000000000000000000101

b >>>= 2   //  00111111111111111111111111111110
console.log(b)
// expected output: 1073741822
Enter fullscreen mode Exit fullscreen mode

I hope you like this reading!

🎁 You can get my new book Underrated skills in javascript, make the difference for FREE if you follow me on Twitter and send message to me 😁 and SAVE 19$ 💵💵

Or get it HERE

🇫🇷🥖 For french developper you can check my YoutubeChannel

🎁 MY NEWSLETTER

☕️ You can SUPPORT MY WORKS 🙏

🏃‍♂️ You can follow me on 👇

🕊 Twitter : https://twitter.com/code__oz

👨‍💻 Github: https://github.com/Code-Oz

And you can mark 🔖 this article!

Top comments (15)

Collapse
 
seanmay profile image
Sean May • Edited

A couple of thoughts, one technical and one subjective:

  1. the ... on the left-hand-side of an assignment statement is also a "rest" operator. "spread" is for expressions (or rhs in statements). When you are putting a bunch of stuff into something, it's a "spread". When you are pulling a bundle of stuff out of something, and giving that bundle a new name, it's a "rest". In functions you are pulling the bundle out of the arguments array
    const f = (x, y, z, ...extraDimensions /*rest of the args*/) => {};
    const [x, y, z, ...extraDimensions /*rest of the array*/] = dimensions;
    const { x, y, z, ...extraDimensions /*rest of the object*/} = dimensions;

  2. I personally feel you should be using ?? at least as often as you are using ?., if not more often. Again, this is the subjective opinion. If you are often using ?. that means you are often getting undefined. If you are passing undefined around, it means that you are often forcing other people (or other parts of the codebase) to do null checking. If you are handling those missing holes in your data with ??, then you have fewer reasons to use ?. farther down the line... Null checking is Sir Tony Hoare's "Billion-Dollar Mistake" and is generally better handled on the outskirts of a system, near the I/O, rather than in the middle of all of the logic... the opinion might be subjective, but it's got a pretty sound backing, by even the inventor of Null (or the person who introduced the concept to programming languages), let alone language researchers.

Collapse
 
codeoz profile image
Code Oz

thanks for replied! I changed a few things for ... operator

Collapse
 
jimmont profile image
Jim Montgomery

Fun article, thanks for it! MDN has some great resources on this topic as well developer.mozilla.org/docs/Web/Jav... developer.mozilla.org/docs/Web/Jav... developer.mozilla.org/docs/Web/Jav...

Collapse
 
yarip28 profile image
Yarip28

Nice sharing! didn't read at all but it seems to be nice!

Collapse
 
codeoz profile image
Code Oz

Thanks Yarip

Collapse
 
qualifymoney profile image
Easy Qualify Money

Perfect work..

Collapse
 
codeoz profile image
Code Oz

thank you a lot

Collapse
 
obaino82 profile image
Obaino82

Perfect work

Collapse
 
codeoz profile image
Code Oz

thanks a lot!

Collapse
 
pengeszikra profile image
Peter Vivo
1 + Math.random() * 6 | 0
Enter fullscreen mode Exit fullscreen mode
Collapse
 
hrrarya profile image
Hridoy Mozumder

Article of the month. Nice.

Collapse
 
codeoz profile image
Code Oz

thank you a lot mate

Collapse
 
karteek_godavarthi profile image
Karteek Godavarthi

Small correction in the code snippet for logical Nullish Coalescing.,
It was mentioned right-handed instead of left-handed.,

Collapse
 
codeoz profile image
Code Oz

thanks it's fixed :D

Collapse
 
codeoz profile image
Code Oz

Very nice feedbacks luke!