index.js
function initCache (cachePath) {
    return new Promise(function (resolve, reject) {
      mkdirp(cachePath, function (err) {
        if (err) {
          reject(err)
        } else {
          resolve()
        }
      })
    })
  }
function initCache (cachePath) {
    return new Promise(function (resolve, reject) {
      mkdirp(cachePath, function (err) {
        if (err) {
          reject(err)
        } else {
          resolve()
        }
      })
    })
  }
function initCache ( cachePath ) { return new Promise ( function ( resolve , reject ) { mkdirp ( cachePath , function ( err ) { if ( err ) { reject ( err ) } else { resolve ( ) } } ) } ) }
check for existing cache folder, if not found, create folder, then resolve
check for existing cache folder if not found create folder then resolve