set(k, v, setOptions = {}) {
        if (v === undefined) {
            this.delete(k);
            return this;
        }
        const { ttl = this.ttl, start, noDisposeOnSet = this.noDisposeOnSet, sizeCalculation = this.sizeCalculation, status, } = setOptions;
        let { noUpdateTTL = this.noUpdateTTL } = setOptions;
        const size = this.#requireSize(k, v, setOptions.size || 0, sizeCalculation);
        // if the item doesn't fit, don't do anything
        // NB: maxEntrySize set to maxSize by default
        if (this.maxEntrySize && size > this.maxEntrySize) {
            if (status) {
                status.set = 'miss';
                status.maxEntrySizeExceeded = true;
            }
            // have to delete, in case something is there already.
            this.delete(k);
            return this;
        }
        let index = this.#size === 0 ? undefined : this.#keyMap.get(k);
        if (index === undefined) {
            // addition
            index = (this.#size === 0
                ? this.#tail
                : this.#free.length !== 0
                    ? this.#free.pop()
                    : this.#size === this.#max
                        ? this.#evict(false)
                        : this.#size);
            this.#keyList[index] = k;
            this.#valList[index] = v;
            this.#keyMap.set(k, index);
            this.#next[this.#tail] = index;
            this.#prev[index] = this.#tail;
            this.#tail = index;
            this.#size++;
            this.#addItemSize(index, size, status);
            if (status)
                status.set = 'add';
            noUpdateTTL = false;
        }
        else {
            // update
            this.#moveToTail(index);
            const oldVal = this.#valList[index];
            if (v !== oldVal) {
                if (this.#hasFetchMethod && this.#isBackgroundFetch(oldVal)) {
                    oldVal.__abortController.abort(new Error('replaced'));
                    const { __staleWhileFetching: s } = oldVal;
                    if (s !== undefined && !noDisposeOnSet) {
                        if (this.#hasDispose) {
                            this.#dispose?.(s, k, 'set');
                        }
                        if (this.#hasDisposeAfter) {
                            this.#disposed?.push([s, k, 'set']);
                        }
                    }
                }
                else if (!noDisposeOnSet) {
                    if (this.#hasDispose) {
                        this.#dispose?.(oldVal, k, 'set');
                    }
                    if (this.#hasDisposeAfter) {
                        this.#disposed?.push([oldVal, k, 'set']);
                    }
                }
                this.#removeItemSize(index);
                this.#addItemSize(index, size, status);
                this.#valList[index] = v;
                if (status) {
                    status.set = 'replace';
                    const oldValue = oldVal && this.#isBackgroundFetch(oldVal)
                        ? oldVal.__staleWhileFetching
                        : oldVal;
                    if (oldValue !== undefined)
                        status.oldValue = oldValue;
                }
            }
            else if (status) {
                status.set = 'update';
            }
        }
        if (ttl !== 0 && !this.#ttls) {
            this.#initializeTTLTracking();
        }
        if (this.#ttls) {
            if (!noUpdateTTL) {
                this.#setItemTTL(index, ttl, start);
            }
            if (status)
                this.#statusTTL(status, index);
        }
        if (!noDisposeOnSet && this.#hasDisposeAfter && this.#disposed) {
            const dt = this.#disposed;
            let task;
            while ((task = dt?.shift())) {
                this.#disposeAfter?.(...task);
            }
        }
        return this;
    }
Add a value to the cache.

Note: if `undefined` is specified as a value, this is an alias for
{@link LRUCache#delete}