A fast way to split small-to-medium sized strings by small string delimiters
npm install @vltpkg/fast-splitThis is a very fast alternative to String.split(), which can be used
to quickly parse a small-to-medium sized string by a given delimiter.
This is about 10% faster for splitting short strings by a short
delimiter. When we have to walk the resulting list for any reason, or
limit the number of items returned, it's an even bigger difference.
2024 M1 macbook pro, using node 20.11.0, v8 version 11.3.244.8-node.17
Counts are operations per ms, splitting the string '1.2.3-asdf+foo' by
the delimiter '.', transforms calling part.toUpperCase(), and limits
at 2 items
``
split 10385.779
fastSplit 10718.341
splitEmptyCheck 9563.721
fastSplitEmptyCheck 11273.537
splitTransformLoop 5722.724
splitTransformMap 6136.161
fastSplitTransform 6438.606
splitLimit 7076.179
fastSplitLimit 13257.948
`js
import { fastSplit } from '@vltpkg/fast-split'
// say we want to split a string on '.' characters
const str = getSomeStringSomehow()
// basic usage, just like str.split('.'), gives us an array
const parts = fastSplit(str, '.')
// get just the first two parts, leave the rest intact
// Note: unlike str.split('.', 3), the 'rest' here will
// include the entire rest of the string.
// If you do str.split('.', 3), then the last item in the
// returned array is truncated at the next delimiter
const [first, second, rest] = fastSplit(str, '.', 3)
// If you need to transform it, say if it's an IPv4 address
// that you want to turn into numbers, you can do that by
// providing the onPart method, which will be slightly faster
// than getting an array and subsequently looping over it
// pass -1 as the limit to give us all parts``
const nums = fastSplit(str, '.', -1, (part, parts, index) =>
Number(s),
)