gistfile1.js

// ...
    methods: {
      show () {
        this.isDisplayed = true
        this.$emit('input', true)
        this.listen(true)
      },
      hide () {
        this.isDisplayed = false
        this.$emit('input', false)
        this.listen(false)
      },
      listen (on: Boolean = true) {
        // So that we won't add or remove same listener twice
        if (this.isListening === on) {
          return
        }

        // Adding or removing listeners.
        if (on) {
          setTimeout(() => {
            document.body.addEventListener('click', this.hide, false)
          })
        } else {
          document.body.removeEventListener('click', this.hide, false)
        }

        // Flag to know if listener is already registered.
        this.isListening = on
      }
    },
// ...