问题
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
回答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.
回答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
来源：https://stackoverflow.com/questions/37722619/javascript-curly-braces-argument-as-function-parameter