@burglekitt/gmt/dist/unix/interval/mergeIntervalsUnix.js

Temporal-based date and time utilities with timezone support and polyfill integration

import { isValidUnixEpochPair } from "../../internal/resolveUnixTimeZone.js";
/**
 * Collapse a list of Unix epoch intervals into the minimum set of non-overlapping intervals.
 *
 * - List-form generalization of `intervalUnionUnix`, which is pairwise only.
 * - Intervals are merged when they overlap or share an endpoint exactly (adjacent intervals
 *   ARE merged).
 * - Order of the input list does not matter; the result is sorted by start.
 * - Returns `[]` for an empty list.
 * - Returns `[]` when `intervals` is not an array, when any element is not a
 *   `{ start, end }` record of finite numeric (or numeric-string) values, or when any element
 *   has `start > end`.
 *
 * @param intervals array of `{ start, end }` records
 * @returns the minimum set of non-overlapping `{ start, end }` records, sorted by start, or `[]` on invalid input
 *
 * @example mergeIntervalsUnix([{ start: 0, end: 1000000 }, { start: 500000, end: 1500000 }]) // [{ start: 0, end: 1500000 }]
 * @example mergeIntervalsUnix([]) // []
 */
export function mergeIntervalsUnix(intervals) {
    if (!Array.isArray(intervals) || intervals.length === 0) {
        return [];
    }
    if (!intervals.every((interval) => interval &&
        typeof interval === "object" &&
        (typeof interval.start === "number" ||
            typeof interval.start === "string") &&
        (typeof interval.end === "number" || typeof interval.end === "string"))) {
        return [];
    }
    const parsed = intervals.map((interval) => ({
        start: typeof interval.start === "number"
            ? interval.start
            : Number(interval.start),
        end: typeof interval.end === "number" ? interval.end : Number(interval.end),
    }));
    if (!parsed.every((interval) => isValidUnixEpochPair(interval.start, interval.end) &&
        interval.start <= interval.end)) {
        return [];
    }
    parsed.sort((a, b) => a.start - b.start);
    const merged = [];
    for (const interval of parsed) {
        const last = merged[merged.length - 1];
        if (last && interval.start <= last.end) {
            if (interval.end > last.end) {
                last.end = interval.end;
            }
        }
        else {
            merged.push({ start: interval.start, end: interval.end });
        }
    }
    return merged;
}