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ES6 .some() with the ternary operator behaves differently

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1

I've noticed a weird behavior with .some() array method and a ternary operator.

It behaves differently when the integer(count) has to be incremented on each true case with and without the curly brackets.

Although, the console.log shows correct truthy on each iteration.

Any thoughts?

> let arr = ['011','202','3300']
undefined
> let count = 0;
undefined
> arr.some(k => k.includes('0') ? count++ : null);
true
> count;
2 // is not correct
> count = 0;
0
> arr.some(k => k.includes('0') ? count++ : null);
false
> count;
3 // correct 
>
> arr.some(k => k.includes('0') ? console.log('true') : null);
true
true
true
false
> arr.some(k => k.includes('0') ? console.log('true') : null);
true
true
true
false

javascript arrays node.js ecmascript-6

share|improve this question

asked Mar 8 at 2:35

Sgryt87Sgryt87

345

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You need to know about fat arrow.... That is your issue. developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… And some() is the wrong thing to be using here.... some() is checking to see if one thing is true.... again, read the documentation for some()
  
  – epascarello
  Mar 8 at 2:40
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Possible duplicate of Arrow function without curly braces
  
  – david
  Mar 8 at 2:46
  

  
  
  
  

add a comment | 

1

I've noticed a weird behavior with .some() array method and a ternary operator.

It behaves differently when the integer(count) has to be incremented on each true case with and without the curly brackets.

Although, the console.log shows correct truthy on each iteration.

Any thoughts?

> let arr = ['011','202','3300']
undefined
> let count = 0;
undefined
> arr.some(k => k.includes('0') ? count++ : null);
true
> count;
2 // is not correct
> count = 0;
0
> arr.some(k => k.includes('0') ? count++ : null);
false
> count;
3 // correct 
>
> arr.some(k => k.includes('0') ? console.log('true') : null);
true
true
true
false
> arr.some(k => k.includes('0') ? console.log('true') : null);
true
true
true
false

javascript arrays node.js ecmascript-6

share|improve this question

asked Mar 8 at 2:35

Sgryt87Sgryt87

345

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You need to know about fat arrow.... That is your issue. developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… And some() is the wrong thing to be using here.... some() is checking to see if one thing is true.... again, read the documentation for some()
  
  – epascarello
  Mar 8 at 2:40
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Possible duplicate of Arrow function without curly braces
  
  – david
  Mar 8 at 2:46
  

  
  
  
  

add a comment | 

I've noticed a weird behavior with .some() array method and a ternary operator.

It behaves differently when the integer(count) has to be incremented on each true case with and without the curly brackets.

Although, the console.log shows correct truthy on each iteration.

Any thoughts?

> let arr = ['011','202','3300']
undefined
> let count = 0;
undefined
> arr.some(k => k.includes('0') ? count++ : null);
true
> count;
2 // is not correct
> count = 0;
0
> arr.some(k => k.includes('0') ? count++ : null);
false
> count;
3 // correct 
>
> arr.some(k => k.includes('0') ? console.log('true') : null);
true
true
true
false
> arr.some(k => k.includes('0') ? console.log('true') : null);
true
true
true
false

javascript arrays node.js ecmascript-6

share|improve this question

asked Mar 8 at 2:35

Sgryt87Sgryt87

345

> let arr = ['011','202','3300']
undefined
> let count = 0;
undefined
> arr.some(k => k.includes('0') ? count++ : null);
true
> count;
2 // is not correct
> count = 0;
0
> arr.some(k => k.includes('0') ? count++ : null);
false
> count;
3 // correct 
>
> arr.some(k => k.includes('0') ? console.log('true') : null);
true
true
true
false
> arr.some(k => k.includes('0') ? console.log('true') : null);
true
true
true
false

share|improve this question

asked Mar 8 at 2:35

Sgryt87Sgryt87

345

share|improve this question

asked Mar 8 at 2:35

Sgryt87Sgryt87

345

asked Mar 8 at 2:35

Sgryt87Sgryt87

345

asked Mar 8 at 2:35

Sgryt87Sgryt87

345

1 Answer
1

active

oldest

votes

2

Let's understand this

Why this one is giving output 2

arr.some(k => k.includes('0') ? count++ : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

• So on first iteration count++ will return 0 and than increment value by 1. ( since it is post increment )




• On second iteration it will return value as 1 which is true and than increment by 1. ( since you found one true value some will stop iteration )

Why this one is giving output 3

arr.some(k => k.includes('0') ? console.log('true') : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

• Here you're not utilizing implicit return of arrow function so on each iteration you're eventually returning undefined. so your some will iterate through all the elements and you get output as 3.

Just add a return statement and see the changes.

let count = 0;
let arr = ['011','202','3300']
arr.some(k => return k.includes('0') ? count++ : null);

console.log(count)

share|improve this answer

edited Mar 8 at 2:51

answered Mar 8 at 2:43

Code ManiacCode Maniac

10.1k2733

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Could add that within nothing is being returned, hence always false. Apparently you read minds since you just added that
  
  – Neil Lunn
  Mar 8 at 2:45
  
  

  
  
  
  

add a comment | 

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2

Let's understand this

Why this one is giving output 2

arr.some(k => k.includes('0') ? count++ : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

• So on first iteration count++ will return 0 and than increment value by 1. ( since it is post increment )




• On second iteration it will return value as 1 which is true and than increment by 1. ( since you found one true value some will stop iteration )

Why this one is giving output 3

arr.some(k => k.includes('0') ? console.log('true') : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

• Here you're not utilizing implicit return of arrow function so on each iteration you're eventually returning undefined. so your some will iterate through all the elements and you get output as 3.

Just add a return statement and see the changes.

let count = 0;
let arr = ['011','202','3300']
arr.some(k => return k.includes('0') ? count++ : null);

console.log(count)

share|improve this answer

edited Mar 8 at 2:51

answered Mar 8 at 2:43

Code ManiacCode Maniac

10.1k2733

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Could add that within nothing is being returned, hence always false. Apparently you read minds since you just added that
  
  – Neil Lunn
  Mar 8 at 2:45
  
  

  
  
  
  

add a comment | 

2

Let's understand this

Why this one is giving output 2

arr.some(k => k.includes('0') ? count++ : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

• So on first iteration count++ will return 0 and than increment value by 1. ( since it is post increment )




• On second iteration it will return value as 1 which is true and than increment by 1. ( since you found one true value some will stop iteration )

Why this one is giving output 3

arr.some(k => k.includes('0') ? console.log('true') : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

• Here you're not utilizing implicit return of arrow function so on each iteration you're eventually returning undefined. so your some will iterate through all the elements and you get output as 3.

Just add a return statement and see the changes.

let count = 0;
let arr = ['011','202','3300']
arr.some(k => return k.includes('0') ? count++ : null);

console.log(count)

share|improve this answer

edited Mar 8 at 2:51

answered Mar 8 at 2:43

Code ManiacCode Maniac

10.1k2733

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Could add that within nothing is being returned, hence always false. Apparently you read minds since you just added that
  
  – Neil Lunn
  Mar 8 at 2:45
  
  

  
  
  
  

add a comment | 

Let's understand this

Why this one is giving output 2

arr.some(k => k.includes('0') ? count++ : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

• So on first iteration count++ will return 0 and than increment value by 1. ( since it is post increment )




• On second iteration it will return value as 1 which is true and than increment by 1. ( since you found one true value some will stop iteration )

Why this one is giving output 3

arr.some(k => k.includes('0') ? console.log('true') : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

• Here you're not utilizing implicit return of arrow function so on each iteration you're eventually returning undefined. so your some will iterate through all the elements and you get output as 3.

Just add a return statement and see the changes.

let count = 0;
let arr = ['011','202','3300']
arr.some(k => return k.includes('0') ? count++ : null);

console.log(count)

share|improve this answer

edited Mar 8 at 2:51

answered Mar 8 at 2:43

Code ManiacCode Maniac

10.1k2733

arr.some(k => k.includes('0') ? count++ : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

arr.some(k => k.includes('0') ? console.log('true') : null);

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

let count = 0;
let arr = ['011','202','3300']
arr.some(k => return k.includes('0') ? count++ : null);

console.log(count)

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

let count = 0;
let arr = ['011','202','3300']
arr.some(k => k.includes('0') ? count++ : null);

console.log(count)

let count = 0;
let arr = ['011','202','3300']
arr.some(k => return k.includes('0') ? count++ : null);

console.log(count)

let count = 0;
let arr = ['011','202','3300']
arr.some(k => return k.includes('0') ? count++ : null);

console.log(count)

share|improve this answer

edited Mar 8 at 2:51

answered Mar 8 at 2:43

Code ManiacCode Maniac

10.1k2733

answered Mar 8 at 2:43

Code ManiacCode Maniac

10.1k2733

answered Mar 8 at 2:43

Code ManiacCode Maniac

10.1k2733