How to use the names in a GraphQLEnumType as the defaultValue of a GraphQL query argument?

Question

When defining a query in a schema, how do I refer to a value of an GraphQLEnumType declared previously, to use it as the default value of an argument?

Let's say I've defined following ObservationPeriod GraphQLEnumType:

observationPeriodEnum = new GraphQLEnumType {
  name: "ObservationPeriod"
  description: "One of the performance metrics observation periods"
  values:
    Daily:
      value: '1D'
      description: "Daily"
    […]
}

and use it as the type of query argument period:

queryRootType = new GraphQLObjectType {
  name: "QueryRoot"
  description: "Query entry points to the DWH."
  fields:
    performance:
      type: performanceType
      description: "Given a portfolio EID, an observation period (defaults to YTD)
                    and as-of date, as well as the source performance engine,
                    return the matching performance metrics."
      args:
        period:
          type: observationPeriodEnum 
          defaultValue: observationPeriodEnum.Daily ← how to achieve this?
      […]
}

Currently I'm using the actual '1D' string value as the default value; this works:

        period:
          type: observationPeriodEnum 
          defaultValue: '1D'

But is there a way I could use the Daily symbolic name instead? I couldn't find a way to use the names within the schema itself. Is there something I overlooked?

I'm asking, because I was expecting an enum type to behave as a set of constants also, and to be able to use them like this in the schema definition:

        period:
          type: observationPeriodEnum 
          defaultValue: observationPeriodEnum.Daily

---

Naïve workaround:

##
# Given a GraphQLEnumType instance, this macro function injects the names 
# of its enum values as keys the instance itself and returns the modified
# GraphQLEnumType instance.
#
modifiedWithNameKeys = (enumType) ->
  for ev in enumType.getValues()
    unless enumType[ ev.name]?
      enumType[ ev.name] = ev.value
    else
      console.warn "SCHEMA> Enum name #{ev.name} conflicts with key of same
        name on GraphQLEnumType object; it won't be injected for value lookup"
  enumType

observationPeriodEnum = modifiedWithNameKeys new GraphQLEnumType {
  name: "description: "Daily""
  values:
    […]

which allows to use it as desired in schema definition:

        period:
          type: observationPeriodEnum 
          defaultValue: observationPeriodEnum.Daily

Of course, this modifier fullfils its promise, only as long as the enum names do not interfere with GraphQLEnumType existing method and variable names (which are currently: name, description, _values, _enumConfig, _valueLookup, _nameLookup, getValues, serialize, parseValue, _getValueLookup, _getNameLookup and toString — see definition of GraphQLEnumType class around line 687 in https://github.com/graphql/graphql-js/blob/master/src/type/definition.js#L687)

Answer 1

I just ran into this. My enum:

const contributorArgs = Object.assign(
  {},
  connectionArgs, {
    sort: {
      type: new GraphQLEnumType({
        name: 'ContributorSort',
        values: {
          top: { value: 0 },
        },
      })
    },
  }
);

In my queries, I was doing:

... on Topic {
  id
  contributors(first: 10, sort: 'top') {
    ...
  }
}

Turns out you just don't quote the value (which after thinking about it makes sense; it's a value in the enum type, not an actual value:

... on Topic {
  id
  contributors(first: 10, sort: top) {
    ...
  }
}