Question

I want to figure out if Array[] and Object[] can be replaced by Array() and Object(). Can a function prototype be stuck into arrays or objects prototype chain to make them callable. Basically I am looking for some thing like this:

// some magic with prototypes
????????????????

a = [1, 3, 4]
b = [1, 3, 4]

console.log(a[1]) // prints 3
console.log(b(1)) // prints 3

a[0] = -1
// same as
b(0, -1)

console.log(a[1], b(1)) // prints -1 -1

Thanks alot!

Answer 1

You probably don’t want to do this, especially in any browser. This doesn’t have a lot of nice features of Array, including efficiency. That said:

function ArrayFunction (arr) {
  var f = function s (p, v) {
    if (v !== undefined) {
      s[p] = v
    }
    return s[p]
  }

  for (var i = 0; i < arr.length; i++) {
    f[i] = arr[i]
  }

  return f
}

var a = new ArrayFunction([1, 3, 4])
var b = new ArrayFunction([1, 3, 4])

b(1, 5)
a[1] //3
b[1] //5

I originally wanted to use prototypes, but objects don’t inherit callableness from their prototypes.

EDIT: Fixed above to not use arguments. This version does not allow you to set a value to undefined, but that’s generally not considered a good practice anyway.