What is the difference between '' and ('')

let n = 'a' + 1

let n = ('a') + 1

let n = ('a') + (1)

what is the difference?

What is the difference between '' and ('')

let n = 'a' + 1

let n = ('a') + 1

let n = ('a') + (1)

what is the difference?

• javascript

Share Improve this question Follow edited Jun 7, 2020 at 8:26 FZs 18.7k1313 gold badges4646 silver badges5656 bronze badges asked Jun 7, 2020 at 8:23 PakuhashiPakuhashi 6911 silver badge22 bronze badges 10

• 2 There is no difference! – Boris Commented Jun 7, 2020 at 8:25
• 1 Just like between 10 and (10) in math... – FZs Commented Jun 7, 2020 at 8:25
• 2 there is no one. parentheses with a single value makes no sense, but does not harm either. – Nina Scholz Commented Jun 7, 2020 at 8:25
• 1 no difference. anywhere you have 'a1' and type will STRING. – Alexandr Erokhov Commented Jun 7, 2020 at 8:27
• 1 () are used for changing the order of execution with lower precedence Operator precedence. if the statements are in the same order then the parenthesis are of no use. – arizafar Commented Jun 7, 2020 at 8:27

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4 Answers 4

Sorted by: Reset to default 8

They are same both.

() is important for precedence especially if there is math operations and concat with string together. Read this info

var example1='x' + (1+2); console.log(example1);
var example2='x'+1+2; console.log(example2);

var example3=("x"+4)/2; console.log(example3);
var example4=("x")+(4/2); console.log(example4);

Taking a property from an object works without parentheses.

var value = { x: 1 }.x;

console.log(value);

Basically the only need for parenthesis is to destructure the item ouside of a declaration.

Does not work

var foo;

{ foo } = { foo: 1 }; // assigment to a block statement

console.log(foo);

Works

var foo;

({ foo } = { foo: 1 });

console.log(foo);

Another use case for parentheses, is by takeing an arrow function which returns an object.

var fn = foo => ({ foo });

console.log(fn(1));

There’s no difference between '' and (''). Parentheses make no difference in your code examples.

Parentheses (), known as the Grouping Operator, are used to change the order of evaluation of an expression. Consider the following expression:

1 + 2 * 3   

As the * operator has higher precedence, first 2 * 3 will be evaluated and then the result of multiplication will be added to 1.

const result = 1 + 2 * 3;

console.log(result);

If you want to do addition first, then you can use ().

(1 + 2) * 3   

Adding parentheses will change how the expression is evaluated. Instead of multiplication, now 1 + 2 will be evaluated first and then the result of addition will be multiplied with 3.

const result = (1 + 2) * 3;

console.log(result);

Grouping Operator ()

Grouping operator implies the precedence of evaluation of an expression or subexpression.

With the grouping operator, it is possible to override the normal precedence of evaluation by telling the piler an expression with lower precedence should be evaluated before an expression with higher priority.

console.log(3 + 4 * 5); // 3 + 20
// expected output: 23

console.log(4 * 3 ** 2); // 4 * 9
// expected output: 36

let a;
let b;

console.log(a = b = 5);
// expected output: 5

https://developer.mozilla/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence