Node.js 合并Shift对象数组以创建最终的排班表

// Helper functions to toggle between DMY and YMD formats, to make dates lexically ordered:
const toggleIso = (s) => s?.replace(/^(\d+)-(\d+)-(\d+) (.*)$/, "$3-$2-$1 $4");
const toggleIsoMap = arr =>
    arr.map(o => ({ ...o, start: toggleIso(o.start), end: toggleIso(o.end) }))
       .sort((a, b) => a.start.localeCompare(b.start));

function mergeShifts(shifts, overrides) {
    overrides = toggleIsoMap(overrides);
    const shiftIter = toggleIsoMap(shifts).values();
    const nextShift = () => shiftIter.next().value;

    const result = [];

    let shift = nextShift();    
    for (const override of overrides) {
        // Flush all shifts that come before this override
        while (shift?.end < override.start) { 
            result.push(shift);
            shift = nextShift();
        }
        // The override may make a shift end sooner
        if (shift?.start < override.start) result.push({...shift, end: override.start });
        result.push(override);
        // Skip shifts that are entirely within the override
        while (shift?.end <= override.end) shift = nextShift();
        // The override may make a shift start later
        if (shift?.start < override.end) shift = {...shift, start: override.end };
    }
    if (shift) result.push(shift);
    return toggleIsoMap(result.concat(...shiftIter));
}

// Run with your example input 
const shifts = [
    {start: "01-07-2023 00:00", end: "02-07-2023 00:00", users: ['a']},
    {start: "02-07-2023 00:00", end: "03-07-2023 00:00", users: ['b']},
    {start: "03-07-2023 00:00", end: "04-07-2023 00:00", users: ['c']},
    {start: "04-07-2023 00:00", end: "05-07-2023 00:00", users: ['a']},
    {start: "05-07-2023 00:00", end: "06-07-2023 00:00", users: ['b']}
];
const overrides = [
    {start: "01-07-2023 10:00", end: "01-07-2023 15:00", users: ['d']},
    {start: "04-07-2023 01:00", end: "05-07-2023 12:00", users: ['e']},
    {start: "02-07-2023 00:00", end: "03-07-2023 00:00", users: ['f']}
];

const result = mergeShifts(shifts, overrides);
for (const entry of result) console.log(JSON.stringify(entry));