Syntax - what does square brackets around a variable declaration mean [duplicate]

Question

Take the following line of code

const [component] = router.getMatchedComponents({ ...to }) 

Could anyone advise what the square brackets around component means here? I have tried to google this but struggling to find an answer

Answer 1

It's called Destructuring assignment, and it's used to unpack the values of an array and assign them to new variables.

So here in your code:

const [component] = router.getMatchedComponents({ ...to }) 

You are assigning to the component variable the first element held in the array that will be returned by router.getMatchedComponents({...to}), where to is an array-like structure turned into object using the spread operation.