define(["require", "exports", "../Dropdown.types"], function (require, exports, Dropdown_types_1) {
    "use strict";
    Object.defineProperty(exports, "__esModule", { value: true });
    /**
     * A utility class to cache size and position in cache.
     *
     * Dropdown options has non-selectable display types. It is therefore not cheap to determine
     * the total number of actual selectable options as well as the position an option is in the
     * list of options - O(n) cost for each lookup.
     *
     * Given that we potentially have to make this determination on every single render pass, this
     * cache should provide a little bit of relief.
     */
    var DropdownSizePosCache = /** @class */ (function () {
        function DropdownSizePosCache() {
            this._size = 0;
        }
        /**
         * Invalidates the cache and recalculate the size of selectable options.
         */
        DropdownSizePosCache.prototype.updateOptions = function (options) {
            var displayOnlyOptionsCache = [];
            var size = 0;
            for (var i = 0; i < options.length; i++) {
                if (options[i].itemType === Dropdown_types_1.DropdownMenuItemType.Divider || options[i].itemType === Dropdown_types_1.DropdownMenuItemType.Header) {
                    displayOnlyOptionsCache.push(i);
                }
                else {
                    size++;
                }
            }
            this._size = size;
            this._displayOnlyOptionsCache = displayOnlyOptionsCache;
        };
        Object.defineProperty(DropdownSizePosCache.prototype, "optionSetSize", {
            /**
             * The size of all the selectable options.
             */
            get: function () {
                return this._size;
            },
            enumerable: true,
            configurable: true
        });
        /**
         * Returns the position of this option element relative to the full set of selectable option elements.
         * Note: the first selectable element is position 1 in the set.
         * @param index The raw index of the option element.
         */
        DropdownSizePosCache.prototype.positionInSet = function (index) {
            if (index === undefined) {
                return undefined;
            }
            // we could possibly memoize this too but this should be good enough, most of the time (the expectation is that
            // when you have a lot of options, the selectable options will heavily dominate over the non-selectable options.
            var offset = 0;
            while (index > this._displayOnlyOptionsCache[offset]) {
                offset++;
            }
            if (this._displayOnlyOptionsCache[offset] === index) {
                throw new Error("Unexpected: Option at index " + index + " is not a selectable element.");
            }
            return index - offset + 1;
        };
        return DropdownSizePosCache;
    }());
    exports.DropdownSizePosCache = DropdownSizePosCache;
});
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