16f6c0aecf
Inline adoc files when they are included exactly once. Also fix language tags because this inlining gives us better information on what language the code is written in.
57 lines
1.3 KiB
Plaintext
57 lines
1.3 KiB
Plaintext
== Why is this an issue?
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Mixing up the order of operations will almost always yield unexpected results.
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Similarly, mis-applied negation will also yield bad results. For instance consider the difference between ``++!key in dict++`` and ``++!(key in dict)++``. The first looks for a boolean value (``++!key++``) in ``++dict++``, and the other looks for a string and inverts the result. ``++!obj instanceof SomeClass++`` has the same problem.
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This rule raises an issue when the left operand of an ``++in++`` or ``++instanceof++`` operator is negated.
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=== Noncompliant code example
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[source,javascript]
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----
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if (!"prop" in myObj) { // Noncompliant; "in" operator is checking property "false"
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doTheThing(); // this block will be never executed
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}
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if (!foo instanceof MyClass) { // Noncompliant; "!foo" returns a boolean, which is not an instance of anything
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doTheOtherThing(); // this block is never executed
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}
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----
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=== Compliant solution
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[source,javascript]
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----
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if (!("prop" in myObj)) {
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doTheThing();
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}
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if (!(foo instanceof MyClass)) {
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doTheOtherThing();
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}
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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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=== Message
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Add parentheses to disambiguate this expression.
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=== Highlighting
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minus operator
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endif::env-github,rspecator-view[]
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