why destructuring object keys gives an error in javascript?

Question

for example, I have an object but when i send this object key inside curly brackets it gives error.

const user = {name: "fishLegs"}
userModerl.create({user.name})

while taking that key inside another variable makes it work fine. Why so?

const user = {name: "fishLegs"}
let userName = user.name
userModerl.create({userName})

CertainPerformance · Accepted Answer · 2021-04-26 04:37:28Z

4

In JavaScript, objects are key-value pairs.

Normally, if you try to list a plain expression (a value) inside an object literal, the syntax will not be valid, because you need both a value and a key. That's why {user.name} fails.

There's an exception, though: if you have a standalone variable (not something that's a property of an object, it needs to be a standalone identifer), listing just that identifier creates a property on the object with the same name as the variable, with a value of what's contained in the variable.

{ someVar }

is equivalent to

{ someVar: someVar }

but such a thing can't be done (and doesn't really make sense) for

{ user.name }

answered Apr 26, 2021 at 4:37

CertainPerformance

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3 Comments

Sebastian Simon Over a year ago

There’s a proposal to make this syntax possible.

fishLegs Over a year ago

so i can write userModel.create({name : user.name}).. makes sense now

fishLegs Over a year ago

i thought it would automatically take that key of the first object and make its own key with same name

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