Why is dot notation invalid for a function variable input parameter Javascript

Question

I have found that this syntax is valid for defining a function

    let path = finalObjs.vendorPath
    const getAllIndexes = (dependenciesResultToHydrateFlat, path) => {

    }

However, this syntax is invalid

    const getAllIndexes = (dependenciesResultToHydrateFlat, finalObjs.vendorPath) => {

    }

Why is it not allowed to use dot notation directly to reference a property value when defining a function? It feels like these two are functionally the same and I don't understand why the latter is invalid. Explanation from the wizards is appreciated.

Those are parameter names, not expressions. That doesn't actually make any sense. — SLaks
– SLaks, Commented May 13, 2019 at 20:30
And let path in your first example doesn't actually do anything. — SLaks
– SLaks, Commented May 13, 2019 at 20:30
Path is equal to the vendorPath field on the finalObjs object — Goldfish
– Goldfish, Commented May 13, 2019 at 20:31
Are you aware that the two instances of path in your first example are completely different entities that just happen to have the same name? Or is that part of your question? — Ray Toal
– Ray Toal, Commented May 13, 2019 at 20:31

julianYaman · Accepted Answer · 2019-05-13 20:52:48Z

1

(I know this might neglect but it could be helpful)

You also can set default values for your function parameters.

Code:

const getAllIndexes = (dependenciesResultToHydrateFlat, path=finalObjs.vendorPath) => {

}

With this, you can change the path afterwards by giving it a value. Otherwise it would use the 'default' value you set to the specific parameter.

answered May 13, 2019 at 20:52

julianYaman

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2 Comments

Goldfish Over a year ago

This is awesome! Thank you kindly

julianYaman Over a year ago

@Goldfish Thank you! Happy to help!

Goldfish · Accepted Answer · 2019-05-13 20:34:09Z

0

Parameters can be named anything, a given parameter is the name that will be assumed for that argument at the time of the function call

answered May 13, 2019 at 20:34

Goldfish

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