53 lines
1.4 KiB
Plaintext
53 lines
1.4 KiB
Plaintext
== Why is this an issue?
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When a non-existent variable is referenced a ``++ReferenceError++`` is raised.
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Due to the dynamic nature of JavaScript this can happen in a number of scenarios:
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* When typo was made in a symbol's name.
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* When using variable declared with ``++let++`` or ``++const++`` before declaration (unlike ``++var++``-declarations, they are not hoisted to the top of the scope).
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* Due to confusion with scopes of ``++let++``- and ``++const++``-declarations (they have block scope, unlike ``++var++``-declarations, having function scope).
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* When accessing a property in the wrong scope (e.g. forgetting to specify ``++this.++``).
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This rule does not raise issues on global variables which are defined with ``++sonar.javascript.globals++`` and ``++sonar.javascript.environments++`` properties.
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=== Noncompliant code example
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[source,javascript]
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----
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var john = {
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firstName: "john",
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show: function() { console.log(firstName); } // Noncompliant: firstName is not defined
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}
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john.show();
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----
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=== Compliant solution
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[source,javascript]
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----
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var john = {
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firstName: "john",
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show: function() { console.log(this.firstName); }
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}
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john.show();
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----
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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include::message.adoc[]
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include::../highlighting.adoc[]
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'''
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== Comments And Links
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(visible only on this page)
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include::../comments-and-links.adoc[]
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endif::env-github,rspecator-view[]
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