Use Rest Operators ( … ) || ES6
What the heck are Three Dots || Rest Operator ?
Same question get arise when I was learning the concepts of ES6. So yeah, first-of-all Rest Operator is the part of ES6.
Now, how they work ? Let See quick -
CASE 1 : Dealing with Arrays.
Suppose i want only two fields ( a, b ) from Array and other fields should be in other parameter (rest).
Here Two Concepts are working together i.e Destructing and Rest Operator.
`a` , `b` , `…rest` are making array into three pieces ( DESTRUCTION ).
`…` is taking all rest things left in one variable.
CASE 2 : Dealing with Objects.
Now let say, we want data from objects.
Here Also Two Concepts are working together i.e Destructing and Rest Operator.
`a` , `b` , `…rest` are making array into three peices ( DESTRUCTION ).
In with `rest` is giving all other objects left.
CASE 3 : Dealing with Complex Objects.
Here, if i want to change the value of `a` in object.
You can do it like -
This will do in the same object !!
What if you want NEW Object having same values of above object and then change the value.
Let’s Try -
NOTE — Notice that both the Objects ( OLD ,NEW ) will be changed,
because Objects Save REFERENCES. So both objects have new updated value of `a`.
I am pretty sure you know that, just Reminding 😜
To Solve the above issue we can use the Saviour ( Rest Operator )
What this will do is ? Any idea ?
It will include whole object inside the NEW object ( as named newObject ) and then modify the key `a` if it is present, else add the new key in object.
What if i change the order -
Nothing will happen here because first we are adding a key `a` in new object then we are modifying that with old object. So this will give the same Result as Old object.
I know what you are saying 😎
I think now you are much clear about Rest Operators.
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