@entria/graphql-mongo-helpers

GraphQL Mongo Helpers

1. What is this?
2. Install
3. Usage

What is this?

It's a package with some (currently one to be exact) tools to use when building a GraphQL API and using MongoDB.

Install

yarn add @entria/graphql-mongo-helpers

Usage

The most updated source of documentation are the test files, check the files in src/__tests__/.

I've written a post about some of those helpers:

buildMongoConditionsFromFilters`(filterArgs, mapping, context)

This helper transforms given object, which is going to be a argument supplied to some resolver, and returns a matching object to be consumed by MongoDB. The object will have a conditions and pipeline property.

input MyResolverFilter {
  # filter field name, can add a suffix which is going to act as a modifier
  # in this case using all
  tags_all: [String!]!
  title: String
}

// some mapping, mappins are optional, the default behavior
// is the filter be a MATCH_1_TO_1 with key identical to the one supplied
const filterMapping = {
  tags: {
    type: FILTER_CONDITION_TYPE.MATCH_1_TO_1,
    key: 'my.nested.tags',
  },
  title: {
    type: FILTER_CONDITION_TYPE.MATCH_1_TO_1,
    // format function can be used to transform the value before creatig the condition
    format: (val) => new RegExp(`^${escapeRegex(val)}`),
  }
}

Then inside the resolver:

const filterResult = buildMongoConditionsFromFilters(args.filter, filterMapping);

if client supplied something like:

{
  tags_all: ['a', 'b'],
  title: 'Blah',
};

the filterResult value will be:

{
  conditions: {
    'my.nested.tags': { $all: ['a', 'b'] },
    title: /^Blah/,
  },
  pipeline: [],
}

Available comparison operators

'gt', 'gte', 'lt', 'lte', 'in', 'nin', 'ne', 'all'

where in, nin and all expect the value of the respective filter to be an array.