Postgraphile plugin to add a default for `first` argument for connection queries

pagination-default.ts

import { makeWrapResolversPlugin } from 'graphile-utils'
import type { GraphQLField } from 'graphql'

const PaginationDefault = makeWrapResolversPlugin(
  ({ scope }) => {
    if (scope.isPgFieldConnection) {
      return { scope }
    }
    return null
  },
  ({ scope }) =>
    async (resolver, _user, args, _context, resolveInfo) => {
      const fieldName = scope.fieldName
      const rootField = resolveInfo.schema.getQueryType()?.getFields()[fieldName]
      if (rootField && hasPaginationArgs(rootField)) {
        if (args.first === undefined && args.last === undefined) {
          // If first and last are both unset, return the first 10 rows.
          args.first = 10
          // Alternative: Return an error if neither first nor last is set.
          // throw new Error('Either `first` or `last` argument is required.')
        }
      }
      // @ts-ignore
      const result = await resolver()
      return result
    },
)

function hasPaginationArgs(field: GraphQLField<any, any>): boolean {
  const hasArg = (name: string) => !!field.args.find((x) => x.name === name)
  return hasArg('first') && hasArg('last')
}

export default PaginationDefault