Requires Array#sort calls to always provide a compareFunction (require-array-sort-compare)
This rule prevents invoking the Array#sort()
method without providing a compare
argument.
When called without a compare function, Array#sort()
converts all non-undefined array elements into strings and then compares said strings based off their UTF-16 code units.
The result is that elements are sorted alphabetically, regardless of their type. When sorting numbers, this results in the classic "10 before 2" order:
This also means that Array#sort
does not always sort consistently, as elements may have custom #toString
implementations that are not deterministic; this trap is noted in the noted in the language specification thusly:
NOTE 2: Method calls performed by the
ToString
abstract operations in steps 5 and 7 have the potential to causeSortCompare
to not behave as a consistent comparison function. > https://www.ecma-international.org/ecma-262/9.0/#sec-sortcompare
Rule Details
This rule aims to ensure all calls of the native Array#sort
method provide a compareFunction
, while ignoring calls to user-defined sort
methods.
Examples of incorrect code for this rule:
Examples of correct code for this rule:
Options
None.
When Not To Use It
If you understand the language specification enough, you can turn this rule off safely.
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