Performant sorting for complex input.
You do not need this library unless you are having performance issues. mapsort does not add any functionality not present in plain JavaScript. Rather, it greatly improves your performance in case:
- sorting is your bottleneck, and
- the elements in your arrays require expensive preprocessing before their correct order can be determined.
Imagine we are sorting this array of numbers, represented as strings:
['12', '1', '3.14']Sorting them with no compare function would place '12' before '3.14', so we need such a function:
['12', '1', '3.14'].toSorted((a, b) => parseFloat(a) - parseFloat(b));This works!
The drawback is that parseFloat is called twice every time our compare function is used. Sorting three numbers results in 6 (or 4) parseFloat calls, of which only 3 are strictly necessary.
3 or 6 parseFloat calls makes no difference. However, next time we might be sorting names. Lucia Ávila would like to appear amidst the other As, thus we have to correctly handle diacritics. Amelie de Wit would like to appear amidst the other Ws, thus we have to detect tussenvoegsels. And the number of calls to the compare function grows loglinearly with the number of names. As our preprocessing becomes more expensive and our arrays become longer, this could produce perceivable hiccups.
mapsort reduces the number of times an element is preprocessed to 1:
mapSort(['12', '1', '3.14'], parseFloat, (a, b) => a - b);Install mapsort using npm or Yarn and import the function:
import mapSort from 'mapsort';Alternatively, include mapsort through unpkg:
<script src="https://unpkg.com/mapsort@^1.0.10"></script>This alternative makes the function available at window.mapSort.
const sortedArray = mapSort(
array,
element => {
// Return the version of "element" which is ideal for
// sorting. This version is passed to the compare
// function below.
},
(a, b) => {
// (Optional.) Return a negative number if a comes
// before b; a positive number if b comes before a; or
// 0 if they are equal.
}
);- This library does not sort in-place, making it more similar to
[].toSortedthan[].sort. - This library probably performs stable sorting.
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