nextId (vm) {
    const path = vm.$route && vm.$route.path ? vm.$route.path : false
    const pathPrefix = path ? vm.$route.path.replace(/[/\\.\s]/g, '-') : 'global'
    if (!Object.prototype.hasOwnProperty.call(this.idRegistry, pathPrefix)) {
      this.idRegistry[pathPrefix] = 0
    }
    return `${this.options.idPrefix}${pathPrefix}-${++this.idRegistry[pathPrefix]}`
  }
Produce a deterministically generated id based on the sequence by which it
was requested. This should be *theoretically* the same SSR as client side.
However, SSR and deterministic ids can be very challenging, so this
implementation is open to community review.