@envelop/core

@envelop/core

This is the core package for Envelop. You can find a complete documentation here: https://github.com/dotansimha/envelop

Built-in plugins

useSchema

This plugin is the simplest plugin for specifying your GraphQL schema. You can specify a schema created from any tool that emits GraphQLSchema object.

import { envelop, useSchema } from '@envelop/core';
import { buildSchema } from 'graphql';

const mySchema = buildSchema(...);

const getEnveloped = envelop({
  plugins: [
    useSchema(mySchema),
    // ... other plugins ...
  ],
});

useErrorHandler

This plugin triggers a custom function every time execution encounter an error.

import { envelop, useErrorHandler } from '@envelop/core';
import { buildSchema } from 'graphql';

const getEnveloped = envelop({
  plugins: [
    useErrorHandler(error => {
      // This callback is called per each GraphQLError emitted during execution phase
    }),
    // ... other plugins ...
  ],
});

Note: every error is being triggered on it's own. So an execution results will multiple error will yield multiple calls.

useExtendContext

Easily extends the context with custom fields.

import { envelop, useExtendContext } from '@envelop/core';
import { buildSchema } from 'graphql';

const getEnveloped = envelop({
  plugins: [
    useExtendContext(async (contextSoFar) => {
      return {
        myCustomField: { ... }
      }
    }),
    // ... other plugins ...
  ],
});

useLogger

Logs paramaters and information about the execution phases. You can easily plug your custom logger.

import { envelop, useLogger } from '@envelop/core';
import { buildSchema } from 'graphql';

const getEnveloped = envelop({
  plugins: [
    useLogger({
      logFn: (eventName, args) => {
        // Event could be `execute-start` / `execute-end` / `subscribe-start` / `subscribe-end`
        // `args` will include the arguments passed to execute/subscribe (in case of "start" event) and additional result in case of "end" event.
      },
    }),
    // ... other plugins ...
  ],
});

usePayloadFormatter

Allow you to format/modify execution result payload before returning it to your consumer.

import { envelop, usePayloadFormatter } from '@envelop/core';
import { buildSchema } from 'graphql';

const getEnveloped = envelop({
  plugins: [
    usePayloadFormatter(result => {
      // Return a modified result here,
      // Or `false`y value to keep it as-is.
    }),
    // ... other plugins ...
  ],
});

useTiming

Simple time metric collection, for every phase in your execution. You can easily customize the behaviour of each timing measurement. By default, the timing is printed to the log, using console.log.

import { envelop, useTiming } from '@envelop/core';
import { buildSchema } from 'graphql';

const getEnveloped = envelop({
  plugins: [
    useTiming({
      // All options are optional. By default it just print it to the log.
      // ResultTiming is an object built with { ms, ns } (milliseconds and nanoseconds)
      onContextBuildingMeasurement: (timing: ResultTiming) => {},
      onExecutionMeasurement: (args: ExecutionArgs, timing: ResultTiming) => {},
      onSubscriptionMeasurement: (args: SubscriptionArgs, timing: ResultTiming) => {},
      onParsingMeasurement: (source: Source | string, timing: ResultTiming) => {},
      onValidationMeasurement: (document: DocumentNode, timing: ResultTiming) => {},
      onResolverMeasurement: (info: GraphQLResolveInfo, timing: ResultTiming) => {},
    }),
    // ... other plugins ...
  ],
});