Installation

npm install graphql --save

Template to run as CLI

var { graphql, buildSchema } = require("graphql")
 
// Construct a schema, using GraphQL schema language
var schema = buildSchema(`
  type Query {
    hello: String
  }
`)
 
// The rootValue provides a resolver function for each API endpoint
var rootValue = {
  hello() {
    return "Hello world!"
  }
}
 
// Run the GraphQL query '{ hello }' and print out the response
graphql({
  schema,
  source: "{ hello }",
  rootValue
}).then(response => {
  console.log(response)
})

Return Value

{
  "data": {
    "hello": "Hello world!"
  }
}

Template to run as server

var express = require("express")
var { createHandler } = require("graphql-http/lib/use/express")
var { buildSchema } = require("graphql")
 
// Construct a schema, using GraphQL schema language
var schema = buildSchema(`
  type Query {
    hello: String
  }
`)
 
// The root provides a resolver function for each API endpoint
var root = {
  hello() {
    return "Hello world!"
  },
}
 
var app = express()
 
// Create and use the GraphQL handler.
app.all(
  "/graphql",
  createHandler({
    schema: schema,
    rootValue: root,
  })
)
 
// Start the server at port
app.listen(4000)
console.log("Running a GraphQL API server at http://localhost:4000/graphql")