Zazama / node-id3

src/util.js

/**
 * @param {any} value
 * @returns {boolean} true if value is a function
 */
 const isFunction = (value) => typeof value === 'function'

The constant isFunction seems to be never used. Consider removing it.

 /**
  * @param {any} value
  * @returns  {boolean} true if value is a string
  */
 const isString = (value) => typeof value === 'string' || value instanceof String

The constant isString seems to be never used. Consider removing it.