JavaScript Curly braces argument as function parameter [duplicate]

Question

I am not very experienced with javascript and have a question relating to curly braces used around a function parameter, since its not a JSON structure.

I am learning nuclear js, and I found some code as example, but I don't understand it well - why is "product" is in braces?:

addToCart(product) {
    reactor.dispatch(ADD_TO_CART, { product })
}

Thx

Answer 1

This is an ES2015 (also called ES6) shorthand to create objects.

{ product } is equivalent to { product: product }.

Basically, you end up with an object with a property called "product" that has the value of the product variable.

const prop = "prop value";
const obj = { prop, anotherProp: "something else" }
console.log("obj: ", obj);

Have a look at the MDN documentation and here if you need a more detailed explanation.

It is a relatively new syntax so old browsers (e.g. IE) are likely to raise a syntax error, however it starts to be quite well supported amongst modern browsers. Have a look here for the ES2015 compatibility table.

Answer 2

This is ES6 shorthand syntax for defining object having same key as the variable name.

{product} is same as { product: product }.

Property Shorthand

MDN Docs