locutus/golang/filepath/Dir.js

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

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Dir = Dir;
function Dir(path) {
    //      discuss at: https://locutus.io/golang/filepath/Dir
    // parity verified: Go 1.23
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Mirrors path/filepath.Dir for slash-separated paths on the Go parity target.
    //       example 1: Dir('/a/b/c.txt')
    //       returns 1: '/a/b'
    //       example 2: Dir('/a/b/')
    //       returns 2: '/a/b'
    //       example 3: Dir('c.txt')
    //       returns 3: '.'
    //       example 4: Dir('')
    //       returns 4: '.'
    const raw = String(path);
    if (raw === '') {
        return '.';
    }
    const slash = raw.lastIndexOf('/');
    if (slash < 0) {
        return '.';
    }
    const dir = raw.slice(0, slash + 1);
    if (dir === '') {
        return '.';
    }
    const rooted = dir.startsWith('/');
    const segments = dir.split('/');
    const stack = [];
    for (const segment of segments) {
        if (segment === '' || segment === '.') {
            continue;
        }
        if (segment === '..') {
            const top = stack.at(-1);
            if (top && top !== '..') {
                stack.pop();
            }
            else if (!rooted) {
                stack.push('..');
            }
            continue;
        }
        stack.push(segment);
    }
    const cleaned = `${rooted ? '/' : ''}${stack.join('/')}`;
    if (cleaned === '') {
        return rooted ? '/' : '.';
    }
    return cleaned;
}