graphile-build-pg/node8plus/plugins/PgConnectionArgFirstLastBeforeAfter.js

Build a GraphQL schema by reflection over a PostgreSQL schema. Easy to customize since it's built with plugins on graphile-build

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;
const base64Decode = str => Buffer.from(String(str), "base64").toString("utf8");
var PgConnectionArgs = function PgConnectionArgs(builder) {
  builder.hook("GraphQLObjectType:fields:field:args", (args, build, context) => {
    const {
      extend,
      getTypeByName,
      graphql: {
        GraphQLInt
      }
    } = build;
    const {
      scope: {
        fieldName,
        isPgFieldConnection,
        isPgFieldSimpleCollection,
        pgFieldIntrospection: source
      },
      addArgDataGenerator,
      Self
    } = context;
    if (!(isPgFieldConnection || isPgFieldSimpleCollection) || !source || source.kind !== "class" && source.kind !== "procedure") {
      return args;
    }
    const Cursor = getTypeByName("Cursor");
    addArgDataGenerator(function connectionFirstLastBeforeAfter({
      first,
      offset,
      last,
      after,
      before
    }) {
      return {
        pgQuery: queryBuilder => {
          if (first != null) {
            queryBuilder.first(first);
          }
          if (offset != null) {
            queryBuilder.offset(offset);
          }
          if (isPgFieldConnection) {
            if (after != null) {
              addCursorConstraint(after, true);
            }
            if (before != null) {
              addCursorConstraint(before, false);
            }
            if (last != null) {
              if (first != null) {
                throw new Error("We don't support setting both first and last");
              }
              if (offset != null) {
                throw new Error("We don't support setting both offset and last");
              }
              queryBuilder.last(last);
            }
          }
          function addCursorConstraint(cursor, isAfter) {
            try {
              const cursorValues = JSON.parse(base64Decode(cursor));
              return queryBuilder.addCursorCondition(cursorValues, isAfter);
            } catch (e) {
              throw new Error("Invalid cursor, please enter a cursor from a previous request, or null.");
            }
          }
        }
      };
    });
    return extend(args, {
      first: {
        description: build.wrapDescription("Only read the first `n` values of the set.", "arg"),
        type: GraphQLInt
      },
      ...(isPgFieldConnection ? {
        last: {
          description: build.wrapDescription("Only read the last `n` values of the set.", "arg"),
          type: GraphQLInt
        }
      } : null),
      offset: {
        description: build.wrapDescription(isPgFieldConnection ? "Skip the first `n` values from our `after` cursor, an alternative to cursor based pagination. May not be used with `last`." : "Skip the first `n` values.", "arg"),
        type: GraphQLInt
      },
      ...(isPgFieldConnection ? {
        before: {
          description: build.wrapDescription("Read all values in the set before (above) this cursor.", "arg"),
          type: Cursor
        },
        after: {
          description: build.wrapDescription("Read all values in the set after (below) this cursor.", "arg"),
          type: Cursor
        }
      } : null)
    }, isPgFieldConnection ? `Adding connection pagination args to field '${fieldName}' of '${Self.name}'` : `Adding simple collection args to field '${fieldName}' of '${Self.name}'`);
  }, ["PgConnectionArgFirstLastBeforeAfter"]);
};
exports.default = PgConnectionArgs;
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