Chain length value

Share a chain long value function , Instead of optional chains  .

//  Chain length value 
    get(source, path, defaultValue = undefined) {
      const paths = path.replace(/\[(\d+)\]/g, '.$1').split('.')
      let result = source
      for (const p of paths) {
        result = Object(result)[p]
        if (result === undefined) {
          return defaultValue
        }
      }
      return result
    },