33 lines
1.1 KiB
Plaintext
33 lines
1.1 KiB
Plaintext
Functions that accept random numbers of arguments use a rest argument (``++... argname++``). This allows you to pass the function each relevant parameter individually. At runtime, those parameters are automatically wrapped in an array. If you pass an array to such a function, it will automatically be re-wrapped in another array, and this double-layering won't be expected by the called function. To avoid that double-layering, use the spread operator (``++...++``arrayToBeExpanded) in the call to expand the array.
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This applies both to manually created arrays, and to arguments that were accepted as rest parameters.
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== Noncompliant Code Example
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----
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collect(new Book(), new Book());
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function collect(...books: Book[]) {
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buy(books); // Noncompliant
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}
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function buy(...things: any[]) {
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console.log(things); // outputs "[ [ Book {}, Book {} ] ]"
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}
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----
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== Compliant Solution
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----
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collect(new Book(), new Book());
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function collect(...books: Book[]) {
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buy(...books);
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}
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function buy(...things: any[]) {
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console.log(things); // outputs "[ Book {}, Book {} ]"
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}
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----
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