empty.js

const Assertion = require('../assert')
const AssertionFailedError = require('./error')
const { template } = require('../utils')
const output = require('../output')

class EmptinessAssertion extends Assertion {
  constructor(params) {
    super(value => {
      if (Array.isArray(value)) {
        return value.length === 0
      }
      return !value
    }, params)
    this.params.type = 'to be empty'
  }

  getException() {
    if (Array.isArray(this.params.value)) {
      this.params.value = `[${this.params.value.join(', ')}]`
    }

    const err = new AssertionFailedError(this.params, "{{customMessage}}expected {{subject}} '{{value}}' {{type}}")

    err.cliMessage = () => {
      const msg = err.template.replace('{{value}}', output.colors.bold('{{value}}')).replace('{{subject}}', output.colors.bold('{{subject}}'))
      return template(msg, this.params)
    }
    return err
  }

  addAssertParams() {
    this.params.value = this.params.actual = arguments[0]
    this.params.expected = []
    this.params.customMessage = arguments[1] ? `${arguments[1]}\n\n` : ''
  }
}

module.exports = {
  Assertion: EmptinessAssertion,
  empty: subject => new EmptinessAssertion({ subject }),
}