Added support for expressions in including (#32)

src/instructions/selecting.ts

@@ -2,7 +2,11 @@ import type { Model } from '@/src/types/model';
 import type { Instructions } from '@/src/types/query';
 import { flatten } from '@/src/utils/helpers';
 import { getFieldFromModel } from '@/src/utils/model';
-import { getSymbol, prepareStatementValue } from '@/src/utils/statement';
+import {
+  getSymbol,
+  parseFieldExpression,
+  prepareStatementValue,
+} from '@/src/utils/statement';
 
 /**
  * Generates the SQL syntax for the `selecting` query instruction, which allows for
@@ -38,19 +42,29 @@ export const handleSelecting = (
   // If additional fields (that are not part of the model) were provided in the
   // `including` instruction, add ephemeral (non-stored) columns for those fields.
   if (instructions.including) {
+    // Filter out any fields whose value is a sub query, as those fields are instead
+    // converted into SQL JOINs in the `handleIncluding` function, which, in the case of
+    // sub queries resulting in a single record, is more performance-efficient, and in
+    // the case of sub queries resulting in multiple records, it's the only way to
+    // include multiple rows of another table.
     const filteredObject = Object.entries(instructions.including)
-      // Filter out any fields whose value is a sub query, as those fields are instead
-      // converted into SQL JOINs in the `handleIncluding` function, which, in the case of
-      // sub queries resulting in a single record, is more performance-efficient, and in
-      // the case of sub queries resulting in multiple records, it's the only way to
-      // include multiple rows of another table.
-      .filter(([_, value]) => {
+      .map(([key, value]) => {
         const symbol = getSymbol(value);
-        const hasQuery = symbol?.type === 'query';
 
-        if (hasQuery) isJoining = true;
-        return !hasQuery;
-      });
+        if (symbol) {
+          if (symbol.type === 'query') {
+            isJoining = true;
+            return null;
+          }
+
+          if (symbol.type === 'expression') {
+            value = parseFieldExpression(model, 'including', symbol.value);
+          }
+        }
+
+        return [key, value];
+      })
+      .filter((entry) => entry !== null);
 
     // Flatten the object to handle deeply nested ephemeral fields, which are the result
     // of developers providing objects as values in the `including` instruction.
@@ -62,6 +76,8 @@ export const handleSelecting = (
       statement += newObjectEntries
         // Format the fields into a comma-separated list of SQL columns.
         .map(([key, value]) => {
+          if (typeof value === 'string' && value.startsWith('"'))
+            return `(${value}) as "${key}"`;
           return `${prepareStatementValue(statementParams, value)} as "${key}"`;
         })
         .join(', ');

tests/instructions/including.test.ts

@@ -312,6 +312,48 @@ test('get single record including ephemeral field', () => {
   ]);
 });
 
+test('get single record including ephemeral field containing expression', () => {
+  const queries: Array<Query> = [
+    {
+      get: {
+        account: {
+          including: {
+            name: {
+              [RONIN_MODEL_SYMBOLS.EXPRESSION]: `${RONIN_MODEL_SYMBOLS.FIELD}firstName || ' ' || ${RONIN_MODEL_SYMBOLS.FIELD}lastName`,
+            },
+          },
+        },
+      },
+    },
+  ];
+
+  const models: Array<Model> = [
+    {
+      slug: 'account',
+      fields: [
+        {
+          slug: 'firstName',
+          type: 'string',
+        },
+        {
+          slug: 'lastName',
+          type: 'string',
+        },
+      ],
+    },
+  ];
+
+  const statements = compileQueries(queries, models);
+
+  expect(statements).toEqual([
+    {
+      statement: `SELECT *, ("firstName" || ' ' || "lastName") as "name" FROM "accounts" LIMIT 1`,
+      params: [],
+      returning: true,
+    },
+  ]);
+});
+
 test('get single record including deeply nested ephemeral field', () => {
   const queries: Array<Query> = [
     {