vanillajs-browser-helpers/scrollParent.js

Collection of convenience code snippets (helpers) that aims to make it a little easier to work with vanilla JS in the browser

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
var isDOMChildNode_1 = __importDefault(require("./isDOMChildNode"));
var viewport_1 = __importDefault(require("./viewport"));
/**
 * Get the parent element that has scrolling
 *
 * @param elm - The element whose scroll parent is determined
 * @return The scroll parent or the viewport
 */
function scrollParent(elm) {
    var vp = viewport_1.default(elm);
    if (!isDOMChildNode_1.default(elm) || elm === vp) {
        return vp;
    }
    var elmPosition = getComputedStyle(elm).position;
    if (elmPosition === 'fixed') {
        return vp;
    }
    var noStaticParent = elmPosition === 'absolute';
    var parent = elm.parentElement;
    while (parent && parent !== document.body) {
        var _a = getComputedStyle(parent), position = _a.position, overflow = _a.overflow, overflowX = _a.overflowX, overflowY = _a.overflowY;
        if (!(noStaticParent && position === 'static')
            && /(auto|scroll)/.test(overflow + overflowY + overflowX)) {
            return parent;
        }
        parent = parent.parentElement;
    }
    return vp;
}
exports.default = scrollParent;