map (cb, thisArg) {
    const data = []
    this.index.visitAll(function (value) {
      data.push(cb.call(thisArg, value))
    })
    return data
  }
Apply a mapping function to all records.

@example
const names = collection.map((user) => user.name);

@method Collection#map
@since 3.0.0
@param {Function} mapFn Mapping function.
@param {*} [thisArg] Context to which to bind `mapFn`.
@returns {Array} The result of the mapping.