Export easy way for plugins to add PG objects to response

[benjie]

e.g. a custom mutation might want to expose a DB object on its payload type; this requires importing queryFromResolveData from graphile-build-pg/node8plus/queryFromResolveData currently plus doing a bunch of boilerplate code - we should simplify this.

e.g.

const queryFromResolveData = require("graphile-build-pg/node8plus/queryFromResolveData");
const debugFactory = require("debug");
const debugSql = debugFactory("graphile-build-pg:sql");

// ...

async resolve(parent, args, context, resolveInfo) {
  // ...custom logic here...

  const {
    pgClient,
  } = context;
  const parsedResolveInfoFragment = parseResolveInfo(resolveInfo);
  const resolveData = getDataFromParsedResolveInfoFragment(
    parsedResolveInfoFragment,
    PayloadType
  );
  const query = queryFromResolveData(
    sql.fragment`app_public.teams`,
    undefined,
    resolveData,
    {},
    builder => {
      builder.where(
        sql.fragment`${builder.getTableAlias()}.uuid = ${sql.value(
          team.uuid
        )}`
      );
    }
  );
  const { text, values } = sql.compile(query);
  if (debugSql.enabled) debugSql(text);
  const { rows: [row] } = await pgClient.query(text, values);
  return {
    team: row,
  };
}

could be packaged up for us; it'd be nice to just pass in the table type, the where clause, the context and resolveInfo and have the rest done for us.

[benjie]

This is now all wrapped up with graphile-utils and documented here: https://www.graphile.org/postgraphile/extending/#the-easy-way-graphile-utils