当前位置：首页 > 软件库 > 大数据 > 数据查询 >

graphql-lodash

授权协议 MIT License

开发语言 Java

所属分类大数据、数据查询

软件类型开源软件

地区不详

投递者贺景铄

操作系统跨平台

开源组织无

适用人群未知

软件官网

软件文档

官方下载

软件概览

GraphQL Lodash

Unleash the power of lodash inside your GraphQL queries

Why?

GraphQL allows to ask for what you need and get exactly that. But what about the shape?GraphQL Lodash gives you the power of lodash right inside your GraphQL Query using @_ directive.

Note: This is an experimental project created to explore the concept of Query and transformation collocation.

We encourage you to try it inside our demo or check detailed walkthrough.

Example queries

Here are a few query examples you can run against StartWars API:

Find the planet with the biggest population

Get gender statistics

Map characters to films they are featured in

Install

npm install --save graphql-lodash

yarn add graphql-lodash

API

`graphqlLodash(query, [operationName])`

query (required) - query string or query AST
operationName (optional) - required only if the query contains multiple operations

Returns

{
  query: string|object,
  transform: Function
}

query - the original query with stripped @_ directives
transform - function that receives response.data as a single argument and returnsthe same data in the intended shape.

Usage Examples

The simplest way to integrate graphql-lodash is to write wrapper function for graphql client of you choice:

import { graphqlLodash } from 'graphql-lodash';

function lodashQuery(queryWithLodash) {
  let { query, transform } = graphqlLodash(queryWithLodash);
  // Make a GraphQL call using 'query' variable as a query
  // And place result in 'result' variable
  ...
  result.data = transform(result.data);
  return result;
}

Fetch example

An example of a simple client based on fetch API:

function executeGraphQLQuery(url, query) {
  return fetch(url, {
    method: 'POST',
    headers: new Headers({"content-type": 'application/json'}),
    body: JSON.stringify({ query: query })
  }).then(response => {
    if (response.ok)
      return response.json();
    return response.text().then(body => {
      throw Error(response.status + ' ' + response.statusText + '\n' + body);
    });
  });
}

function lodashQuery(url, queryWithLodash) {
  let { query, transform } = window.GQLLodash.graphqlLodash(queryWithLodash);
  return executeGraphQLQuery(url, query).then(result => {
    result.data = transform(result.data);
    return result;
  });
}

// then use as bellow
lodashQuery('https://swapi.apis.guru', `{
  planetWithMaxPopulation: allPlanets @_(get: "planets") {
    planets @_(maxBy: "population") {
      name
      population
    }
  }
}`).then(result => console.log(result.data));

Caching clients

For caching clients like Relay and Apollo we recommend to apply the transformation after the caching layer.Here is proposed solution for Relay:

We are still figuring out how to do this and any feedback is welcome.

Usage with react-apollo

When using with Apollo you can use props option to apply transformations:

const rawQuery = gql`
  # query with @_ directives
`;

const {query, transform} = graphqlLodash(rawQuery);
export default graphql(query, {
  props: (props) => ({...props, rawData: props.data, data: transform(props.data)})
})(Component);

You can write a simple wrapper for simplicity:

import { graphql } from 'react-apollo';
import { graphqlLodash } from 'graphql-lodash';

export function gqlLodash(rawQuery, config) {
  const {query, transform} = graphqlLodash(rawQuery);
  let origProps = (config && config.props) || ((props) => props);

  return (comp) => graphql(query, {...config,
    props: (props) => origProps({
      ...props,
      rawData: props.data,
      data: transform(props.data)
    })
  })(comp);
}
// then use as bellow
export default gqlLodash(query)(Component);

Just replace graphql with gqlLodash and you are ready to use lodash in your queries.Check out the react-apollo-lodash-demo repo.

You can also do the transformation inside an ApolloLink by rewriting theparsed GraphQL Document:

new ApolloLink((operation, forward) => {
  const { query, transform } = graphqlLodash(operation.query);
  operation.query = query;
  return forward(operation)
    .map(response => ({
      ...response,
      data: transform(response.data),
    }));
});

Chaining this link with the other links passed to your ApolloClientwill apply the transformation to every query thatApollo runs, such as those from the <Query /> component orsubscriptions.

Introspection queries

If your application uses introspection queries (like GraphiQL does toget documentation and autocomplete information), you will also need toextend the introspection query result with the directives fromgraphql-lodash. One way you could do this is:

import {
  buildClientSchema,
  extendSchema,
  graphqlSync,
  introspectionQuery,
} from 'graphql';

// inside the above ApolloLink function
if (response.data && response.data.__schema) {
  const schema = extendSchema(
    buildClientSchema(response.data),
    lodashDirectiveAST,
  );
  return graphqlSync(schema, introspectionQuery);
}

See the demo/ source in this repo for another example of modifyingthe introspection query result.

Usage on server side

In theory, this tool can be used on the server. But this will break the contract and, most likely,will break all the GraphQL tooling you use. Use it on server-side only if you know what you do.

使用案例

JS实现lodash的get方法

使用场景在 js 中经常会出现嵌套调用这种情况，如 a.b.c.d.e，但是这么写很容易抛出异常。你需要这么写 a && a.b && a.b.c && a.b.c.d && a.b.c.d.e，但是显得有些啰嗦与冗长了。特别是在 graphql 中，这种嵌套调用更是难以避免。这时就需要一个 get 函数，使用 get(a, 'b.c.d.e') 简单清晰，并且容错性提高了很多
如何实现类似 lodash 的 get 与 merge 函数

lodash 基本上成为了写 javascript 工具库的标配，它广泛应用在各种服务端以及前端应用中，但是它的包体积略大了一些。对于服务端来说，包的体积并不是十分的重要，或者换句话说，不像前端那样对包的体积特别敏感，一分一毫都会影响页面打开的性能，从而影响用户体验。正因为前端包体积对于用户体验的重要性，因此有各种各样减小包体积的方法。针对 lodash 来说，你完全不必要引入 lodash 的