cacheGet (key) {
    try {
      const resultRaw = window.localStorage.getItem(this.getCacheKey(key))
      if (resultRaw) {
        const resultDecoded = JSON.parse(resultRaw)
        if (resultDecoded.cacheBuster && resultDecoded.schema) {
          if (resultDecoded.cacheBuster === this.getCacheBuster()) {
            return resultDecoded.schema
          }
        }
        this.cacheDelete(key)
      }
    } catch (e) {
      // eslint-disable-next-line no-console
      console.error(e)
    }
  }
Fetches a schema from localStorage cache.

@param {string} key
  The schema's key, e.g., URL.

@returns {mixed}
  If found, returns the schema.