JavaScript difference between ' ' and (' ')

Question

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

let n = 'a' + 1

let n = ('a') + 1

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

what is the difference?

Answer 1

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);

Answer 2

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));

Answer 3

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);