how to check the arrary length?

`const Schema = require('validate')

let params = {
  oneName: []
}

const schema = new Schema({
  oneName: {
    type: Array,
    minLen: 1,
    message: {
      minLen: 'array is not empty'
    }
  }
})

const errors = schema.validate(params)
console.log('errors', errors)`

why it occurs the error 'oneName must be of type Object'?
