TypeScript + Gatsby node API

createPages.ts

import { resolve } from 'path'
import { GatsbyCreatePages } from './types'

const createPages: GatsbyCreatePages = async ({
  graphql,
  boundActionCreators,
}) => {
  const { createPage } = boundActionCreators

  const allMarkdown = await graphql(`
    {
      allMarkdownRemark(limit: 1000) {
        edges {
          node {
            fields {
              slug
            }
          }
        }
      }
    }
  `)

  allMarkdown.data.allMarkdownRemark.edges.forEach(edge => {
    const { slug } = edge.node.fields
    if (!slug) return

    // type safe `createPage` call
    createPage({
      path: slug,
      component: resolve(__dirname, '../src/templates/index.tsx'),
      context: {
        slug,
      },
    })
  })
}

gatsby-node.js

'use strict'

require('source-map-support').install()
require('ts-node').register({
  compilerOptions: {
    module: 'commonjs',
    target: 'es2017',
  },
})

exports.createPages = require('./createPages')

types.ts

interface PageInput {
  path: string
  component: string
  layout?: string
  context?: any
}

interface BoundActionCreators {
  createPage: (page: PageInput) => void
  deletePage: (page: PageInput) => void
  createRedirect: (
    opts: {
      fromPath: string
      isPermanent?: boolean
      redirectInBrowser?: boolean
      toPath: string
    }
  ) => void
}

export type GatsbyCreatePages = (
  fns: { graphql: any; boundActionCreators: BoundActionCreators }
) => void

@crhistianramirez same - it fixes the TypeError: gatsbyNode[api] is not a function problems

@crhistianramirez please, could you explain why your change fixed this error?

Hi, shall we write types.ts or types.d.ts? IMHO maybe that suits the definition of d.ts