apollo-link-core/src/test-utils/setContext.ts

Flexible, lightweight transport layer for GraphQL

import { Operation, NextLink, FetchResult } from '../types';

import Observable from 'zen-observable-ts';

import { ApolloLink } from '../link';

export default class SetContextLink extends ApolloLink {
  constructor(
    private setContext: (
      context: Record<string, any>,
    ) => Record<string, any> = c => c,
  ) {
    super();
  }

  public request(
    operation: Operation,
    forward: NextLink,
  ): Observable<FetchResult> {
    if (!operation.context) {
      operation.context = {};
    }
    operation.context = this.setContext(operation.context);
    return forward(operation);
  }
}