Why "new Array" after variable?

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Why put new Array after the variable name?
Example:

var weatherPattern = new Array('Clouds', "raining", "clowdy");
javascript array oop variable-declaration

  • Why not put it? What’s the point of the question? Give more details, context than you want to know. Are you willing to compare it to some other way?

  • I see an example where the person creates an array and before the array puts that new Array, wanted to know if there is any meaning or put by.

1 answer

5


This is one way to declare a array in Javascript, you call a function Array() which should precisely generate the array to assign to the variable. O new is used to indicate the object allocation. It has no secret, it is the same as other nonprimitive objects.

There is the syntax where the array is created as a literal in the language. The effect is the same and becomes more concise and even more readable.

In this example I do not see why not use the literal, as shown below, the effect is the same, so if they used it should be a matter of style. Otherwise I’d have to ask who did it, because technically it’s the same thing.

var weatherPattern = new Array('Clouds', "raining", "clowdy");
var weatherPattern = ['Clouds', "raining", "clowdy")];

In some JS interpreters it may be that one works faster than another, but this is not always guaranteed.

But the following are different:

var weatherPattern = new Array(5);
var weatherPattern = [5];

I put in the Github for future reference.

The first creates a array and reserves 5 positions to allocate objects, the second creates a array with a numeric element worth 5, they are very different things. In this case the argument passed to the function Array() does not behave as an element of array and yes as a size setting parameter array.

There’s one more trick. The function Array() can do something different than expected since JS allows it to be overwritten. It may not even create a array. Of course no programmer should do this, but it can. Which is still a possible interesting trick.

Javascript has these oddities even.

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