43 lines
927 B
Plaintext
43 lines
927 B
Plaintext
The unary operators ``+`` and ``++-++`` can be used to convert some value types to numeric values. But not every value can be converted to a ``++Number++`` type; use it with an object, and result will be ``++NaN++`` (Not A Number). This can be confusing to maintainers.
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== Noncompliant Code Example
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----
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var obj = {x : 1};
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doSomethingWithNumber(+obj); // Noncompliant
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function foo(){
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return 1;
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}
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doSomethingWithNumber(-foo); // Noncompliant
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----
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== Compliant Solution
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----
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var obj = {x : 1};
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doSomethingWithNumber(+obj.x);
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function foo(){
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return 1;
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}
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doSomethingWithNumber(-foo());
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var str = '42';
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doSomethingWithNumber(+str);
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----
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== Exceptions
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Unary ``{plus}`` and ``++-++`` can be used with objects corresponding to primitive types, and ``{plus}`` can be used with ``++Date++``.
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----
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var b = new Boolean(true);
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doSomethingWithNumber(-b); // Compliant
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var timestamp = +new Date(); // Compliant
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----
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