Use of setting null in function

Question

I was following a tutorial online and they set the predefined value of the function as null(data and details), what is the use of the null, what does it mean

onClick={(data, details = null) => {
        console.log(data.description, details);
      }}

Possible duplicate of Set a default parameter value for a JavaScript function — Prashant Pimpale
– Prashant Pimpale, Commented May 25, 2019 at 4:48

Arosha · Accepted Answer · 2019-05-25 05:17:35Z

2

I think you know what is the notation of putting null in parameters and Set a default parameter value for a JavaScript function explains it further.

There are usages of putting default value to null.

You can easily check whether values are assigned with lesser code. ex: if(details){}
You can directly send that to database as a null value.
You may do not prefer default undefined value based on your application requirements

Hope this helps.

answered May 25, 2019 at 5:17

Arosha

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Steve Hynding · Accepted Answer · 2019-05-25 05:19:40Z

1

null is a false-evaluated ("falsey") JavaScript object type whereas an empty object (like one defined via {}) is a true-evaluated ("truthy") object.

In many situations I have seen, developers will use it to signify the parameter is expecting an object because typeof null === "object". Without the details = null, a missing details parameter would be undefined, a type all of its own (typeof undefined === "undefined").

answered May 25, 2019 at 5:19

Steve Hynding

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