apollo/README.md

Apollo in Vue

Integrates apollo in your vue components with declarative queries.

Installation

npm install vue-apollo

Usage

Configuration

import Vue from 'vue';
import ApolloClient from 'apollo-client';
import VueApollo from 'vue-apollo'

const apolloClient = new ApolloClient({
  /* ... */
});

Vue.use(VueApollo, {
  apolloClient,
});

Usage in components

To declare apollo queries in your Vue component, add an apollo object :

new Vue({
    apollo: {
        // Apollo specific options
    }
});

You can access the apollo-client instance with this.$apollo.client in all your vue components.

Queries

In the data object, add an attribute for each property you want to feed with the result of an Apollo query.

Simple query

Put the gql query directly as the value:

apollo: {
  // Non-reactive query
  data: {
    // Simple query that will update the 'hello' vue property
    hello: gql`{hello}`
  }
}

Don't forget to initialize your property in your vue component:

data () {
  return {
    // Initialize your apollo data
    hello: ''
  }
}

Server-side, add the corresponding schema and resolver:

export const schema = `
type Query {
  hello: String
}

schema {
  query: Query
}
`;

export const resolvers = {
  Query: {
    hello(root, args, context) {
      return "Hello world!";
    }
  }
};

For more info, visit the apollo doc.

You can then use your property as usual in your vue component:

<template>
  <div class="apollo">
    <h3>Hello</h3>
    <p>
      {{hello}}
    </p>
  </div>
</template>

Query with parameters

You can add variables (read parameters) to your gql query by declaring query and variables in an object:

// Apollo-specific options
apollo: {
  // Non-reactive query
  data: {
    // Query with parameters
    ping: {
      // gql query
      query: gql`query PingMessage($message: String!) {
        ping(message: $message)
      }`,
      // Static parameters
      variables: {
        message: 'Meow'
      }
    }
  }
}

You can use the following apollo options in the object:

• forceFetch
• fragments

See the apollo doc for more details.

For example, you could add the forceFetch apollo option like this:

apollo: {
  data: {
    // Query with parameters
    ping: {
      query: gql`query PingMessage($message: String!) {
        ping(message: $message)
      }`,
      variables: {
        message: 'Meow'
      },
      // Additional options here
      forceFetch: true
    }
  }
}

Don't forget to initialize your property in your vue component:

data () {
  return {
    // Initialize your apollo data
    ping: ''
  }
}

Server-side, add the corresponding schema and resolver:

export const schema = `
type Query {
  ping(message: String!): String
}

schema {
  query: Query
}
`;

export const resolvers = {
  Query: {
    ping(root, { message }, context) {
      return `Answering ${message}`;
    }
  }
};

And then use it in your vue component:

<template>
  <div class="apollo">
    <h3>Ping</h3>
    <p>
      {{ping}}
    </p>
  </div>
</template>

Reactive parameters

Use a function instead to make the parameters reactive with vue properties:

// Apollo-specific options
apollo: {
  // Non-reactive query
  data: {
    // Query with parameters
    ping: {
      query: gql`query PingMessage($message: String!) {
        ping(message: $message)
      }`,
      // Reactive parameters
      variables() {
        // Use vue reactive properties here
        return {
            message: this.pingInput
        }
      }
    }
  }
}

This will re-fetch the query each time a parameter changes, for example:

<template>
  <div class="apollo">
    <h3>Ping</h3>
    <input v-model="pingInput" placeholder="Enter a message" />
    <p>
      {{ping}}
    </p>
  </div>
</template>

Advanced options

These are the available advanced options you can use:

• update(data) {return ...} to customize the value that is set in the vue property, for example if the field names don't match
• result(data) is a hook called when a result is received
• error(errors, type) is a hook called when there are errors, type value can either be 'sending' or 'execution'
• loadingKey will update the component data property you pass as the value. You should initialize this property to 0 in the component data() hook. When the query is loading, this property will be incremented by 1 and as soon as it no longer is, the property will be decremented by 1. That way, the property can represent a counter of currently loading queries.
• watchLoading(isLoading, countModifier) is a hook called when the loading state of the query changes. The countModifier parameter is either equal to 1 when the query is now loading, or -1 when the query is no longer loading.

// Apollo-specific options
apollo: {
  // Non-reactive query
  data: {
    // Advanced query with parameters
    // The 'variables' method is watched by vue
    pingMessage: {
      query: gql`query PingMessage($message: String!) {
        ping(message: $message)
      }`,
      // Reactive parameters
      variables() {
        // Use vue reactive properties here
        return {
            message: this.pingInput
        }
      },
      // We use a custom update callback because
      // the field names don't match
      // By default, the 'pingMessage' attribute
      // would be used on the 'data' result object
      // Here we know the result is in the 'ping' attribute
      // considering the way the apollo server works
      update(data) {
        console.log(data);
        // The returned value will update
        // the vue property 'pingMessage'
        return data.ping;
      },
      // Optional result hook
      result(data) {
        console.log("We got some result!");
      },
      // Error handling
      error(errors, type) {
        console.error(`We've got ${errors.length} errors of type '${type}'`);
      },
      // Loading state
      // loadingKey is the name of the data property
      // that will be incremented when the query is loading
      // and decremented when it no longer is.
      loadingKey: 'loadingQueriesCount',
      // watchLoading will be called whenever the loading state changes
      watchLoading(isLoading, countModifier) {
        // isLoading is a boolean
        // countModifier is either 1 or -1
      }
    }
  }
}

If you use ES2015, you can also write the update like this:

update: data => data.ping

Reactive Queries

For now, the reactivity in apollo is quite limited, since you can only do polling.

For more info, see the apollo doc.

Add your queries in a watch object instead of data:

// Apollo-specific options
apollo: {
  // Reactive query
  watch: {
    // 'tags' data property on vue instance
    tags: {
      query: gql`{
        tags {
          id,
          label
        }
      }`,
      pollInterval: 300 // ms
    }
  }
}

You can use the apollo options, for example:

• forceFetch
• returnPartialData
• pollInterval
• fragments

See the apollo doc for more details.

You can also use the advanced options detailed above, like result or watchLoading.

Here is how the server-side looks like:

export const schema = `
type Tag {
  id: Int
  label: String
}

type Query {
  tags: [Tag]
}

schema {
  query: Query
}
`;

// Fake word generator
import casual from 'casual';

// Let's generate some tags
var id = 0;
var tags = [];
for (let i = 0; i < 42; i++) {
  addTag(casual.word);
}

function addTag(label) {
  let t = {
    id: id++,
    label
  };
  tags.push(t);
  return t;
}

export const resolvers = {
  Query: {
    tags(root, args, context) {
      return tags;
    }
  }
};

Mutations

Mutations are queries that changes your data state on your apollo server. For more info, visit the apollo doc.

methods: {
  addTag() {
    // Mutate the tags data
    // You can also use this.$apollo.client.mutate
    this.$apollo.mutate({
      mutation: gql`mutation AddTag($label: String!) {
        addTag(label: $label) {
          id,
          label
        }
      }`,
      // Parameters
      variables: {
        label: this.tagLabel
      }
    }).then((data) => {
      // Result
      console.log(data);
      this.tagLabel = '';
    }).catch((error) => {
      // Error
      console.error(error);
    });
  }
}

Server-side:

export const schema = `
type Tag {
  id: Int
  label: String
}

type Query {
  tags: [Tag]
}

type Mutation {
  addTag(label: String!): Tag
}

schema {
  query: Query
  mutation: Mutation
}
`;

// Fake word generator
import faker from 'faker';

// Let's generate some tags
var id = 0;
var tags = [];
for (let i = 0; i < 42; i++) {
  addTag(faker.random.word());
}

function addTag(label) {
  let t = {
    id: id++,
    label
  };
  tags.push(t);
  return t;
}

export const resolvers = {
  Query: {
    tags(root, args, context) {
      return tags;
    }
  },
  Mutation: {
    addTag(root, { label }, context) {
      console.log(`adding tag '${label}'`);
      return addTag(label);
    }
  }
};

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