object-destructuring.md

Object Destructuring

Destructuring in Function Argument

You should use object destructuring in function argument to pick out what you need.

// bad
function foo(prop) {
  return prop.a + prop.b
}

// good
function foo({ a, b }) { return a + b }

Why?

When you have a function taking in an object, the object may contain things that you don't need.

Using object spread give the reader a clear statement that those are the only properties you are interested in.

This is expecially valuable if the interface of the parameter is defined by other code.

Why not?

If you do functional programming, you are likely to use a context parameter as the first parameter, and you need to pass the context down to other functions.

In this case, you need all properties in the context variables, not only those you use within your function.

In that case, do object destructuring in the function body.

function foo(context) {
  const { io, record } = context
}

Of course, if the parameter is an instance of a class, or an object that aware of this, then you cannot destructure.