Support relation query modifiers, count modifier

src/index.js

@@ -69,6 +69,46 @@ function applyFilterArgument(query, filter) {
 	return query;
 }
 
+function applyModifiersToQuery(query, { filter, orderBy, skip, limit }) {
+	if (filter != null) {
+		query = applyFilterArgument(query, filter);
+	}
+
+	if (orderBy != null) {
+		let ascending = !orderBy.startsWith("-");
+		
+		let orderField = (ascending === true)
+			? orderBy
+			: orderBy.slice(1);
+
+		query = query.orderBy(orderField, (ascending === true) ? "asc" : "desc");
+	}
+
+	if (skip != null) {
+		query = query.offset(skip);
+	}
+
+	if (limit != null) {
+		query = query.limit(limit);
+	}
+
+	return query;
+}
+
+function resultsToType(result, first, makeType) {
+	if (first === true) {
+		if (result.length > 0) {
+			return makeType(result[0].id);
+		} else {
+			return null;
+		}
+	} else {
+		return result.map((item) => {
+			return makeType(item.id);
+		});
+	}
+}
+
 module.exports = {
 	lessThan: function (value) {
 		return {
@@ -141,18 +181,29 @@ module.exports = {
 				sourceColumn: foreignKey.column,
 			};
 
-			remoteTypes[remoteTypeName][remoteField] = async function(_, { $make, $getProperty, knex }) {
+			remoteTypes[remoteTypeName][remoteField] = async function({ count, filter, orderBy, skip, limit, first }, { $make, $getProperty, knex }) {
 				let tx = (knex ?? globalKnex);
 	
 				let result = await wrapErrors(async () => {
-					return tx(tableName).columns("id").where({
-						[idFieldName]: await $getProperty(this, primaryKey)
-					});
-				});
+					if (count === true) {
+						let query = tx(tableName).count("id").first();
+						query = applyModifiersToQuery(query, { filter });
+						return query;
+					} else {
+						let query = tx(tableName).columns("id").where({
+							[idFieldName]: await $getProperty(this, primaryKey)
+						});
 	
-				return result.map((item) => {
-					return $make(typeName, { id: item.id });
+						query = applyModifiersToQuery(query, { filter, orderBy, skip, limit });
+						return query;
+					}
 				});
+	
+				if (count === true) {
+					return parseInt(result.count);
+				} else {
+					return resultsToType(result, first, (id) => $make(typeName, { id: id }));
+				}
 			};
 		});
 
@@ -228,48 +279,27 @@ module.exports = {
 			},
 			rootQueries: {
 				// top-level stuff? but expect the developer to place that in a specific location
-				list: async function ({ filter, orderBy, skip, limit, first }, { $make, knex }) {
+				list: async function ({ count, filter, orderBy, skip, limit, first }, { $make, knex }) {
 					let tx = (knex ?? globalKnex);
 	
-					let query = tx(tableName).column(primaryKey);
-	
-					if (filter != null) {
-						query = applyFilterArgument(query, filter);
-					}
-	
-					if (orderBy != null) {
-						let ascending = !orderBy.startsWith("-");
-						
-						let orderField = (ascending === true)
-							? orderBy
-							: orderBy.slice(1);
-	
-						query = query.orderBy(orderField, (ascending === true) ? "asc" : "desc");
-					}
-	
-					if (skip != null) {
-						query = query.offset(skip);
-					}
-	
-					if (limit != null) {
-						query = query.limit(limit);
-					}
-	
-					let result = await wrapErrors(async () => {
-						return query;
-					});
-	
-					// TODO: Map result(s) to types
-					if (first === true) {
-						if (result.length > 0) {
-							return $make(typeName, { id: result[0].id });
-						} else {
-							return null;
-						}
+					if (count === true) {
+						let query = tx(tableName).count(primaryKey).first();
+						query = applyModifiersToQuery(query, { filter });
+
+						let result = await wrapErrors(async () => {
+							return query;
+						});
+
+						return parseInt(result.count);
 					} else {
-						return result.map((item) => {
-							return $make(typeName, { id: item.id });
+						let query = tx(tableName).column(primaryKey);
+						query = applyModifiersToQuery(query, { filter, orderBy, skip, limit });
+		
+						let result = await wrapErrors(async () => {
+							return query;
 						});
+	
+						return resultsToType(result, first, (id) => $make(typeName, { id: id }));
 					}
 				},
 				delete: async function ({ filter }, { knex }) {