rspec/rules/S2123/javascript/rule.adoc

== Why is this an issue?

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=== Noncompliant code example

[source,javascript]
----
function pickNumber() {
  let i = 0;
  i = i++; // Noncompliant; i is still zero

  return i++; // Noncompliant; 0 returned
}
----

=== Compliant solution

[source,javascript]
----
function pickNumber() {
  let i = 0;
  i++;

  return ++i;
}
----

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'''
== Implementation Specification
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include::../message.adoc[]

'''
== Comments And Links
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=== on 16 Mar 2015, 13:31:43 Pierre-Yves Nicolas wrote:
Raising issues on "return i{plus}{plus}" would lead to false positives because variable i can be referenced and used by other places in the code: it could be an object property and it could also be referenced by a closure.

=== on 16 Mar 2015, 14:34:31 Ann Campbell wrote:
I'm confused, [~pierre-yves.nicolas]. The original code examples showed post-incrementing a method-scope var...?

=== on 16 Mar 2015, 14:46:43 Pierre-Yves Nicolas wrote:
\[~ann.campbell.2]: the following example illustrates the case of a closure which keeps a reference on a variable:

----
function f(x) {
  var i = 0;
  x.y = function () { return i; };
  return i++;
}
var z = {};
f(z); // 0
z.y(); // 1
----
I don't think we can currently raise issues on "return i{plus}{plus};" without false positives.

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