Question

I would want to set the elements of an array of a struct in its creation. Is it possible?

Now, in the first I’ve to define the struct and then set the array

function struct(a, b) {
    this.a=a;
    this.b=b;
}

var foo = [
    new struct(1,2),
    new struct(3,4),
]

but I would want an anoynymous function, anything like:

var foo = function(a, b) [
    (1,2),
    (3,4),
]

Note: it’s incorrect but you see the idea

Answer 1

What you want to use is the object literal notation in addition to the array literal notation.

var foo = [
  {a:1,b:2},
  {a:3,b:4}
];
console.log(foo[0].b); //-> 2

If you really want to call a function, you have to give it a name (though it can be a short one):

function s(a,b){
  return {a:a,b:b};
}
var foo = [
  s(1,2),
  s(3,4)
];

You don’t need to use the new keyword to create a new object; you can set up a new instance—and even set the prototype-based inheritance—all within a normal function call.