32 lines
1014 B
Plaintext
32 lines
1014 B
Plaintext
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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----
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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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----
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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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