rspec/rules/S2434/javascript/rule.adoc

== Why is this an issue?

Defining a object's methods inside the object itself means that a new instance of the function is created for each instantiation of the object, bloating the instances. 


Instead, it is more efficient to define the functions outside the object using the ``++prototype++`` keyword. This yields a single instance of each function, to which all the objects of that type refer.


=== Noncompliant code example

[source,javascript]
----
function Person(firstName, middleInitial, lastName) {
  this.firstName = firstName;
  this.middleInitial = middleInitial;
  this.lastName = lastName;

  this.nameReversed = function() {  // Noncompliant
    return this.lastName + ", " + this.firstName + " " + this.middleInitial;
  }
}
----


=== Compliant solution

[source,javascript]
----
function Person(firstName, middleInitial, lastName) {
  this.firstName = firstName;
  this.middleInitial = middleInitial;
  this.lastName = lastName;
}

Person.prototype.nameReversed = function() {
  return this.lastName + ", " + this.firstName + " " + this.middleInitial;
}
----


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Move this definition outside the "xxx" object and name it "xxx.prototype.yyy".


'''
== Comments And Links
(visible only on this page)

=== on 13 Nov 2015, 14:47:43 Linda Martin wrote:
OK!

endif::env-github,rspecator-view[]