locutus/esm/swift/String/split.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

export function split(str, separator, maxSplits = Number.MAX_SAFE_INTEGER, omittingEmptySubsequences = true) {
    //  discuss at: https://locutus.io/swift/String/split/
    // original by: Kevin van Zonneveld (https://kvz.io)
    //      note 1: Mirrors Swift String.split semantics with configurable max splits and empty-subsequence handling.
    //   example 1: split('a,b,c', ',')
    //   returns 1: ['a', 'b', 'c']
    //   example 2: split('a,,b,', ',', Number.MAX_SAFE_INTEGER, false)
    //   returns 2: ['a', '', 'b', '']
    //   example 3: split('a,b,c,d', ',', 2)
    //   returns 3: ['a', 'b', 'c,d']
    const source = String(str);
    const needle = String(separator);
    const max = Number.isFinite(maxSplits) && maxSplits >= 0 ? Math.floor(maxSplits) : Number.MAX_SAFE_INTEGER;
    if (needle === '') {
        const chars = Array.from(source);
        return omittingEmptySubsequences ? chars.filter((part) => part.length > 0) : chars;
    }
    const out = [];
    let start = 0;
    let splits = 0;
    while (splits < max) {
        const next = source.indexOf(needle, start);
        if (next < 0) {
            break;
        }
        const part = source.slice(start, next);
        if (!omittingEmptySubsequences || part.length > 0) {
            out.push(part);
        }
        start = next + needle.length;
        splits += 1;
    }
    const tail = source.slice(start);
    if (!omittingEmptySubsequences || tail.length > 0) {
        out.push(tail);
    }
    return out;
}