feat: create ObjectParser

Author: nodkz

.eslintrc

@@ -9,7 +9,7 @@
     "arrow-body-style": 0,
     "no-unused-expressions": 0,
     "no-plusplus": 0,
-    "import/no-extraneous-dependencies": ["error", {"devDependencies": ["**/*-test.js", "**/__mocks__/**"]}],
+    "import/no-extraneous-dependencies": ["error", {"devDependencies": ["**/*-test.js", "**/__mocks__/**", "**/__fixtures__/**"]}],
     "no-prototype-builtins": 0,
     "no-restricted-syntax": 0,
     "no-mixed-operators": 0,
@@ -18,16 +18,17 @@
       "objects": "always-multiline",
       "imports": "always-multiline",
       "exports": "always-multiline",
-      "functions": "ignore",
+      "functions": "ignore"
     }],
     "prettier/prettier": ["error", {
       "printWidth": 100,
       "singleQuote": true,
-      "trailingComma": "es5",
+      "trailingComma": "es5"
     }],
     "import/prefer-default-export": 0,
     "arrow-parens": 0,
-    "prefer-destructuring": 0
+    "prefer-destructuring": 0,
+    "no-use-before-define": 0
   },
   "env": {
     "jasmine": true,
@@ -42,5 +43,6 @@
     "Iterator": true,
     "$Shape": true,
     "$Keys": true,
+    "$FlowFixMe": true
   }
 }

package.json

@@ -42,10 +42,13 @@
     "eslint-plugin-flowtype": "^2.39.1",
     "eslint-plugin-import": "^2.8.0",
     "eslint-plugin-prettier": "^2.3.1",
+    "express": "^4.16.2",
+    "express-graphql": "^0.6.11",
     "flow-bin": "^0.57.3",
     "graphql": "^0.11.7",
     "graphql-compose": "^2.9.2",
     "jest": "^21.2.1",
+    "node-fetch": "^1.7.3",
     "prettier": "^1.7.4",
     "rimraf": "^2.6.2",
     "semantic-release": "^8.2.1"
@@ -69,6 +72,7 @@
     "lint": "eslint --ext .js ./src",
     "flow": "./node_modules/.bin/flow",
     "test": "npm run coverage && npm run lint && npm run flow",
-    "semantic-release": "semantic-release pre && npm publish && semantic-release post"
+    "semantic-release": "semantic-release pre && npm publish && semantic-release post",
+    "fixture-demo": "./node_modules/.bin/babel-node ./src/__fixtures__/app.js"
   }
 }

src/ObjectParser.js

@@ -0,0 +1,73 @@
+/* @flow */
+
+import { graphql, TypeComposer, upperFirst } from 'graphql-compose';
+
+const { isOutputType } = graphql;
+
+type GetValueOpts = {
+  typeName: string,
+  fieldName: string,
+};
+
+export default class ObjectParser {
+  static createTC(name: string, json: Object): TypeComposer {
+    if (!json || typeof json !== 'object') {
+      throw new Error('You provide empty object in second arg for `createTC` method.');
+    }
+    const tc = TypeComposer.create(name);
+
+    const fields = {};
+    Object.keys(json).forEach(k => {
+      fields[k] = this.getValueType(json[k], { typeName: name, fieldName: k });
+    });
+
+    tc.setFields(fields);
+
+    return tc;
+  }
+
+  static getValueType(
+    value: any,
+    opts: ?GetValueOpts
+  ): string | [string] | graphql.GraphQLOutputType | TypeComposer {
+    const typeOf = typeof value;
+
+    if (typeOf === 'number') return 'Float';
+    if (typeOf === 'string') return 'String';
+    if (typeOf === 'boolean') return 'Boolean';
+
+    if (typeOf === 'object') {
+      if (value === null) return 'JSON';
+
+      if (Array.isArray(value)) {
+        const val = value[0];
+        if (Array.isArray(val)) return ['JSON'];
+        return [(this.getValueType(val): any)];
+      }
+
+      if (opts && opts.typeName && opts.fieldName) {
+        return this.createTC(`${opts.typeName}_${upperFirst(opts.fieldName)}`, value);
+      }
+    }
+
+    if (typeOf === 'function') {
+      return this.getValueTypeFromFunction(value);
+    }
+
+    return 'JSON';
+  }
+
+  static getValueTypeFromFunction(
+    value: () => any
+  ): string | graphql.GraphQLOutputType | TypeComposer {
+    const type = value();
+
+    if (typeof type === 'string') return type;
+    if (isOutputType(type)) return type;
+    if (type instanceof TypeComposer) return type;
+
+    throw new Error(
+      'Your type function should return: `string`, `GraphQLOutputType`, `TypeComposer`.'
+    );
+  }
+}

src/__fixtures__/Film.js

@@ -0,0 +1,71 @@
+/* @flow */
+
+import fetch from 'node-fetch';
+import composeWithRest from '../index';
+import { PeopleTC } from './People';
+
+const responseFromRestApi = {
+  title: 'The Empire Strikes Back',
+  episode_id: 5,
+  opening_crawl: 'It is a dark time for ...',
+  director: 'Irvin Kershner',
+  producer: 'Gary Kurtz, Rick McCallum',
+  release_date: '1980-05-17',
+  characters: [
+    'https://swapi.co/api/people/1/',
+    'https://swapi.co/api/people/2/',
+    'https://swapi.co/api/people/3/',
+  ],
+};
+
+export const FilmTC = composeWithRest('Film', responseFromRestApi);
+
+// //////////////
+// RESOLVERS aka FieldConfig in GraphQL
+// //////////////
+
+FilmTC.addResolver({
+  name: 'findById',
+  type: FilmTC,
+  args: {
+    id: 'Int!',
+  },
+  resolve: rp => {
+    return fetch(`https://swapi.co/api/films/${rp.args.id}/`).then(r => r.json());
+  },
+});
+
+FilmTC.addResolver({
+  name: 'findByUrl',
+  type: FilmTC,
+  args: {
+    url: 'String!',
+  },
+  resolve: rp => fetch(rp.args.url).then(r => r.json()),
+});
+
+FilmTC.addResolver({
+  name: 'findByUrlList',
+  type: [FilmTC],
+  args: {
+    urls: '[String]!',
+  },
+  resolve: rp => {
+    return Promise.all(rp.args.urls.map(url => fetch(url).then(r => r.json())));
+  },
+});
+
+// //////////////
+// RELATIONS
+// //////////////
+
+FilmTC.addRelation('characters', {
+  resolver: () => PeopleTC.getResolver('findByUrlList'),
+  prepareArgs: {
+    urls: source => source.characters,
+  },
+});
+
+FilmTC.addFields({
+  currentTime: { type: 'String', resolve: () => Date.now() },
+});

src/__fixtures__/People.js

@@ -0,0 +1,69 @@
+/* @flow */
+
+import fetch from 'node-fetch';
+import { FilmTC } from './Film';
+import composeWithRest from '../index';
+
+const responseFromRestApi = {
+  name: 'Luke Skywalker',
+  height: '172',
+  mass: '77',
+  hair_color: 'blond',
+  skin_color: 'fair',
+  eye_color: 'blue',
+  birth_year: '19BBY',
+  gender: 'male',
+  films: [
+    'https://swapi.co/api/films/2/',
+    'https://swapi.co/api/films/6/',
+    'https://swapi.co/api/films/3/',
+  ],
+};
+
+export const PeopleTC = composeWithRest('People', responseFromRestApi);
+
+// //////////////
+// RESOLVERS aka FieldConfig in GraphQL
+// //////////////
+
+PeopleTC.addResolver({
+  name: 'findById',
+  type: PeopleTC,
+  args: {
+    id: 'Int!',
+  },
+  resolve: rp => {
+    return fetch(`https://swapi.co/api/people/${rp.args.id}/`).then(r => r.json());
+  },
+});
+
+PeopleTC.addResolver({
+  name: 'findByUrl',
+  type: PeopleTC,
+  args: {
+    url: 'String!',
+  },
+  resolve: rp => fetch(rp.args.url).then(r => r.json()),
+});
+
+PeopleTC.addResolver({
+  name: 'findByUrlList',
+  type: [PeopleTC],
+  args: {
+    urls: '[String]!',
+  },
+  resolve: rp => {
+    return Promise.all(rp.args.urls.map(url => fetch(url).then(r => r.json())));
+  },
+});
+
+// //////////////
+// RELATIONS
+// //////////////
+
+PeopleTC.addRelation('filmObjs', {
+  resolver: () => FilmTC.getResolver('findByUrlList'),
+  prepareArgs: {
+    urls: source => source.films,
+  },
+});

src/__fixtures__/Schema.js

@@ -0,0 +1,16 @@
+/* @flow */
+
+import { GQC } from 'graphql-compose';
+import { FilmTC } from './Film';
+import { PeopleTC } from './People';
+
+GQC.rootQuery().addFields({
+  film: FilmTC.getResolver('findById'),
+  people: PeopleTC.getResolver('findById'),
+  peopleByUrl: PeopleTC.getResolver('findByUrl'),
+  peopleByUrls: PeopleTC.getResolver('findByUrlList'),
+});
+
+const schema = GQC.buildSchema();
+
+export default schema;

src/__fixtures__/app.js

@@ -0,0 +1,22 @@
+/* @flow */
+
+import express from 'express';
+import graphqlHTTP from 'express-graphql';
+import schema from './Schema';
+
+const PORT = 4000;
+const app = express();
+
+app.use(
+  '/graphql',
+  graphqlHTTP(req => ({
+    schema,
+    graphiql: true,
+    context: req,
+  }))
+);
+
+app.listen(PORT, () => {
+  console.log(`App running on port ${PORT}`);
+  console.log(`Open http://localhost:${PORT}/graphql`);
+});