How to use the apollo-angular-link-http-common.prioritize function in apollo-angular-link-http-common

const pick = (
          key: K,
          init?: Context[K] | Options[K],
        ): Context[K] | Options[K] => {
          return prioritize(context[key], this.options[key], init);
        };

return Math.random()
        .toString(36)
        .substr(2, 9);
    }

    const headers =
      context.headers &&
      context.headers.keys().map((k: string) => context.headers.get(k));

    const opts = JSON.stringify({
      includeQuery: context.includeQuery,
      includeExtensions: context.includeExtensions,
      headers,
    });

    return prioritize(context.uri, this.options.uri) + opts;
  }

return operations.map(operation => {
      const includeExtensions = prioritize(
        operation.getContext().includeExtensions,
        this.options.includeExtensions,
        false,
      );
      const includeQuery = prioritize(
        operation.getContext().includeQuery,
        this.options.includeQuery,
        true,
      );

      const body: Body = {
        operationName: operation.operationName,
        variables: operation.variables,
      };

      if (includeExtensions) {
        body.extensions = operation.extensions;
      }

      if (includeQuery) {
        body.query = print(operation.query);

private createOptions(operations: Operation[]): Options {
    const context: Context = operations[0].getContext();

    return {
      method: prioritize(context.method, this.options.method, defaults.method),
      uri: prioritize(context.uri, this.options.uri, defaults.uri),
      withCredentials: prioritize(
        context.withCredentials,
        this.options.withCredentials,
      ),
    };
  }

private createOptions(operations: Operation[]): Options {
    const context: Context = operations[0].getContext();

    return {
      method: prioritize(context.method, this.options.method, defaults.method),
      uri: prioritize(context.uri, this.options.uri, defaults.uri),
      withCredentials: prioritize(
        context.withCredentials,
        this.options.withCredentials,
      ),
    };
  }