Gatsby Node API

const path = require(`path`)

exports.createPages = ({ graphql, actions }) => {
  const { createPage } = actions
  const blogPostTemplate = path.resolve(`src/templates/blog-post.js`)
  // Query for markdown nodes to use in creating pages.
  // You can query for whatever data you want to create pages for e.g.
  // products, portfolio items, landing pages, etc.
  // Variables can be added as the second function parameter
  return graphql(`
    query loadPagesQuery ($limit: Int!) {
      allMarkdownRemark(limit: $limit) {
        edges {
          node {
            frontmatter {
              slug
            }
          }
        }
      }
    }
  `, { limit: 1000 }).then(result => {
    if (result.errors) {
      throw result.errors
    }

    // Create blog post pages.
    result.data.allMarkdownRemark.edges.forEach(edge => {
      createPage({
        // Path for this page — required
        path: `${edge.node.frontmatter.slug}`,
        component: blogPostTemplate,
        context: {
          // Add optional context data to be inserted
          // as props into the page component.
          //
          // The context data can also be used as
          // arguments to the page GraphQL query.
          //
          // The page "path" is always available as a GraphQL
          // argument.
        },
      })
    })
  })
}

exports.createResolvers = ({ createResolvers }) => {
  const resolvers = {
    Author: {
      fullName: {
        resolve: (source, args, context, info) => {
          return source.firstName + source.lastName
        }
      },
    },
    Query: {
      allRecentPosts: {
        type: [`BlogPost`],
        resolve: async (source, args, context, info) => {
          const { entries } = await context.nodeModel.findAll({ type: `BlogPost` })
          return entries.filter(
            post => post.publishedAt > Date.UTC(2018, 0, 1)
          )
        }
      }
    }
  }
  createResolvers(resolvers)
}

exports.createSchemaCustomization = ({ actions }) => {
  const { createTypes, createFieldExtension } = actions

  createFieldExtension({
    name: 'shout',
    extend: () => ({
      resolve(source, args, context, info) {
        return String(source[info.fieldName]).toUpperCase()
      }
    })
  })

  const typeDefs = `
    type MarkdownRemark implements Node @dontInfer {
      frontmatter: Frontmatter
    }
    type Frontmatter {
      title: String!
      tagline: String @shout
      date: Date @dateformat
      image: File @fileByRelativePath
    }
  `
  createTypes(typeDefs)
}

exports.onCreateBabelConfig = ({ actions }) => {
  actions.setBabelPlugin({
    name: `babel-plugin-that-i-like`,
    options: {}
  })
}

exports.onCreateDevServer = ({ app }) => {
  app.get('/hello', function (req, res) {
    res.send('hello world')
  })
}

exports.onCreateNode = ({ node, actions }) => {
  const { createNode, createNodeField } = actions
  // Transform the new node here and create a new node or
  // create a new node field.
}

exports.onCreateWebpackConfig = ({
 stage, getConfig, rules, loaders, actions
}) => {
  actions.setWebpackConfig({
    module: {
      rules: [
        {
          test: 'my-css',
          use: [loaders.style(), loaders.css()]
        },
      ],
    },
  });
}

let createJobV2
exports.onPluginInit = ({ actions }) => {
  // store job creation action to use it later
  createJobV2 = actions.createJobV2
}

exports.onPostBuild = ({ reporter, basePath, pathPrefix }) => {
 reporter.info(
  `Site was built with basePath: ${basePath} & pathPrefix: ${pathPrefix}`
 );
};

exports.onPreInit = ({ actions }) => {

}

exports.pluginOptionsSchema = ({ Joi }) => {
  return Joi.object({
    // Validate that the anonymize option is defined by the user and is a boolean
    anonymize: Joi.boolean().required(),
  })
}

import { GraphQLString } from "gatsby/graphql"

exports.setFieldsOnGraphQLNodeType = ({ type }) => {
  if (type.name === `File`) {
    return {
      newField: {
        type: GraphQLString,
        args: {
          myArgument: {
            type: GraphQLString,
          }
        },
        resolve: (source, fieldArgs) => {
          return `Id of this node is ${source.id}.
                  Field was called with argument: ${fieldArgs.myArgument}`
        }
      }
    }
  }

  // by default return empty object
  return {}
}

exports.shouldOnCreateNode = ({node}, pluginOptions) => node.internal.type === 'Image'

exports.sourceNodes = ({ actions, createNodeId, createContentDigest }) => {
  const { createNode } = actions

  // Data can come from anywhere, but for now create it manually
  const myData = {
    key: 123,
    foo: `The foo field of my node`,
    bar: `Baz`
  }

  const nodeContent = JSON.stringify(myData)

  const nodeMeta = {
    id: createNodeId(`my-data-${myData.key}`),
    parent: null,
    children: [],
    internal: {
      type: `MyNodeType`,
      mediaType: `text/html`,
      content: nodeContent,
      contentDigest: createContentDigest(myData)
    }
  }

  const node = Object.assign({}, myData, nodeMeta)
  createNode(node)
}