What are the Advantages and Disadvantages of using Array over a Function

Question

Which if the following two methods is the best / most practical to use?

var arr = (new function (){
    this.Foo = "Foo";
    this.Bar = "Bar";
});

OR

var arr = new Array (
    Foo = "Foo",
    Bar = "Bar"
)

I understand that both of the above can have properties added to them, Please note there is currently no application of the above code so no context around the question, but which is more preferred? Thanks

The first code fragment defines a constructor for a "class" with "properties" Foo and Bar and then immediately instantiates it. The second code fragment creates an array with elements "Foo" and "Bar" (and in the process creates two new global variables Foo and Bar). Whether you want an object with two properties, or an array with two elements, is up to you. — user663031
– user663031, Commented Aug 11, 2016 at 14:26
If you wish to put that as an answer i would be happyto accept :) — P Clegg
– P Clegg, Commented Aug 11, 2016 at 14:29
You should avoid the second method, because it not do what you expect it should do, and it is dangerous as it create global variables. if you need objects use object literals, instead. — Mario Santini
– Mario Santini, Commented Aug 11, 2016 at 14:31

user663031 · Accepted Answer · 2016-08-11 14:34:26Z

1

The first code fragment defines a constructor for an object with properties named Foo and Bar, and then immediately instantiates it with new.

The second code fragment creates an array with elements "Foo" and "Bar" (and in the process creates two new global variables Foo and Bar, which you probably don't want).

Whether you want an object with two properties, or an array with two elements, is up to you.

answered Aug 11, 2016 at 14:34

user663031

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Comments

Maxx · Accepted Answer · 2016-08-11 14:35:37Z

0

Both are really bad. First equals just var arr = {Foo: "Foo", Bar: "Bar"}

In second you create array, but when you do Foo = "Foo" inside you actually declare global var Foo, because Foo = "Foo" is an expression that returns "Foo" for array element.

edited Aug 11, 2016 at 14:35

user663031

answered Aug 11, 2016 at 14:32

Maxx

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2 Comments

djechlin Over a year ago

They're not "equal" in the first case, e.g. constructor property is different. I'm sure there's deeper differences.

Maxx Over a year ago

@djechlin yes, but case where you use this arr.constructor is very wierd. There are some little differences, but code not going to be good with them.

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