TheAlgorithms/JavaScript · error · RangeError

LFUCache ERROR: The Capacity is 0

Error message

LFUCache ERROR: The Capacity is 0

What it means

LFUCache.set() refuses to store when the cache was constructed with capacity 0, because there is no room to hold any entry. The constructor permits 0 (a no-op cache), but set() treats it as a programmer error rather than silently dropping the value.

Source

Thrown at Cache/LFUCache.js:178

    }

    this.misses++
    return null
  }

  /**
   * @method set
   * @description - This method stored the value by key & add frequency if it doesn't exist
   * @param {string} key
   * @param {any} value
   * @param {number} frequency
   * @returns {LFUCache}
   */
  set(key, value, frequency = 1) {
    key = String(key) // converted to string

    if (this.#capacity === 0) {
      throw new RangeError('LFUCache ERROR: The Capacity is 0')
    }

    if (this.cache.has(key)) {
      const node = this.cache.get(key)
      node.value = value

      this.#frequencyMap.refresh(node)

      return this
    }

    // if the cache size is full, then it's delete the Least Frequency Used node
    if (this.#capacity === this.cache.size) {
      this.#removeCacheNode()
    }

    const newNode = new CacheNode(key, value, frequency)

View on GitHub (pinned to 5c39e87a9a)

Solutions

1. Construct with capacity >= 1 if you intend to store values.
2. Guard call sites: only call set() when cache.capacity > 0.
3. Reconfigure capacity upward before inserting if it was set to 0 at startup.

Example fix

// before
const cache = new LFUCache(config.cacheSize ?? 0)
cache.set('k', v)
// after
const cache = new LFUCache(Math.max(1, config.cacheSize ?? 16))
cache.set('k', v)

function safeSet(cache, key, value) {
  if (cache.capacity > 0) cache.set(key, value);
}

try { cache.set(key, value); }
catch (e) {
  if (e instanceof RangeError && /Capacity is 0/.test(e.message)) {
    // cache disabled: skip or store elsewhere
  } else throw e;
}

When it happens

Trigger: Constructing new LFUCache(0) (or resizing capacity to 0) and then calling .set(key, value).

Common situations: Reading capacity from a config that defaults to 0 when disabled, feature-flag disabling a cache but leaving set() calls active, or a size computed from data length that collapsed to 0.

Related errors

• Invalid capacity
• Capacity should be greater than 0
• Grid must be a non-empty array
• Both keyword and message must be specified
• Invalid keyword!

AI-assisted analysis of TheAlgorithms/JavaScript@5c39e87a9a (2026-08-13). Data as JSON: /api/errors/8ecc7b2a993f26c4. Report an issue: GitHub.