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.
49 lines
1.3 KiB
Plaintext
49 lines
1.3 KiB
Plaintext
== Why is this an issue?
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Unlike in JavaScript, where every parameter can be omitted, in TypeScript you need to explicitly declare this in the function signature. Either you add ``++?++`` in the parameter declaration and ``++undefined++`` will be automatically applied to this parameter. Or you add an initializer with a default value in the parameter declaration. In the latter case, when passing ``++undefined++`` for such parameter, default value will be applied as well. So it's better to avoid passing ``++undefined++`` value to an optional or default parameter because it creates more confusion than it brings clarity. Note, that this rule is only applied to the last arguments in function call.
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=== Noncompliant code example
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[source,javascript]
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----
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function foo(x: number, y: string = "default", z?: number) {
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// ...
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}
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foo(42, undefined); // Noncompliant
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foo(42, undefined, undefined); // Noncompliant
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foo(42, undefined, 5); // OK, there is no other way to force default value for second parameter
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----
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=== Compliant solution
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[source,javascript]
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----
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function foo(x: number, y: string = "default", z?: number) {
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// ...
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}
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foo(42);
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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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Remove this redundant "undefined".
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=== Highlighting
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"undefined"
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endif::env-github,rspecator-view[]
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