change nullable generic to type union (#69)

.changeset/cuddly-maps-press.md

@@ -0,0 +1,6 @@
+---
+"@ts-safeql/eslint-plugin": patch
+"@ts-safeql/generate": patch
+---
+
+Change autofix fromNullable generic (e.g. `Nullable<string>`) to type union format (e.g. string | null)

demos/basic-migrations-raw/src/index.ts

@@ -1,10 +1,10 @@
-import { Db, Nullable } from "@ts-safeql-demos/shared/client";
+import { Db } from "@ts-safeql-demos/shared/client";
 import postgres from "postgres";
 
 export function check(client: Db) {
   const sql = postgres();
 
-  client.queryOne<{ id: number; post_id: Nullable<number>; body: Nullable<string> }>(sql`
+  client.queryOne<{ id: number; post_id: number | null; body: string | null }>(sql`
     SELECT * FROM comments
   `);
 }

demos/big-project/src/original.ts

@@ -1,17 +1,15 @@
 import postgres from "postgres";
 
-type Nullable<T> = T | null;
-
 interface Starship {
   id: number;
   name: string;
-  captain_id: Nullable<number>;
+  captain_id: number | null;
 }
 
 export function check() {
   const sql = postgres();
 
   sql<{ id: number }[]>`SELECT id FROM starship`;
-  sql<{ id: number; name: string; captain_id: Nullable<number> }[]>`SELECT * FROM starship`;
+  sql<{ id: number; name: string; captain_id: number | null }[]>`SELECT * FROM starship`;
   sql<Starship[]>`SELECT * FROM starship`;
 }

demos/multi-connections/src/index.ts

@@ -1,12 +1,12 @@
-import { Db, Nullable } from "@ts-safeql-demos/shared/client";
+import { Db } from "@ts-safeql-demos/shared/client";
 import postgres from "postgres";
 
 export function check(client1: Db, client2: Db) {
   const sql = postgres();
 
   // client 1 points to acme/migrations1/
-  client1.queryOne<{ post_id: Nullable<number> }>(sql`SELECT post_id FROM comments`);
+  client1.queryOne<{ post_id: number | null }>(sql`SELECT post_id FROM comments`);
 
   // client 2 points to acme/migrations2/
-  client2.queryOne<{ name: Nullable<string> }>(sql`SELECT name  FROM chat_rooms`);
+  client2.queryOne<{ name: string | null }>(sql`SELECT name  FROM chat_rooms`);
 }

demos/prisma/src/prisma.test.ts

@@ -1,8 +1,6 @@
 import { Prisma, PrismaClient } from "@prisma/client";
 import assert from "assert";
 
-type Nullable<T> = T | null;
-
 import { config } from "dotenv";
 import path from "path";
 
@@ -20,9 +18,9 @@ async function run() {
 
   test(`SELECT * FROM "User"`, async () => {
     return assert.deepEqual(
-      await prisma.$queryRaw<
-        { id: number; createdAt: Date; email: string; name: Nullable<string> }[]
-      >(Prisma.sql`SELECT * FROM "User"`),
+      await prisma.$queryRaw<{ id: number; createdAt: Date; email: string; name: string | null }[]>(
+        Prisma.sql`SELECT * FROM "User"`
+      ),
       await prisma.user.findMany()
     );
   });

demos/prisma/src/prisma.ts-test.ts

@@ -1,8 +1,6 @@
 import { Prisma, PrismaClient, PrismaPromise } from "@prisma/client";
 import { assert, IsExact } from "conditional-type-checks";
 
-type Nullable<T> = T | null;
-
 function _test() {
   const prisma = new PrismaClient();
 
@@ -16,7 +14,7 @@ function _test() {
 
   () => {
     const raw = prisma.$queryRaw<
-      { id: number; createdAt: Date; email: string; name: Nullable<string> }[]
+      { id: number; createdAt: Date; email: string; name: string | null }[]
     >(Prisma.sql`SELECT * FROM "User"`);
     const orm = prisma.user.findMany();
 

demos/shared/client.ts

@@ -20,5 +20,4 @@ export function createClient() {
   return { query, queryOne };
 }
 
-export type Nullable<T> = T | null;
 export type Db = ReturnType<typeof createClient>;

docs/api/index.md

@@ -226,8 +226,8 @@ to be an array of objects, you can use the following:
 ::: tip EXAMPLES
 
 - `"${type}[]"` will transform the type to an array of the type.
-- `["Nullable", "Maybe"]` will replace `Nullable` with `Maybe` in the type.
-- `["${type}[]", ["Nullable", "Maybe"]]` will do both
+- `["colname", "x_colname"]` will replace `colname` with `x_colname` in the type.
+- `["${type}[]", ["colname", x_colname"]]` will do both
 
 :::
 

packages/eslint-plugin/src/rules/check-sql.rule.ts

@@ -44,8 +44,8 @@ const baseSchema = z.object({
    *
    * For example:
    *  - `"${type}[]"` will transform the type to an array
-   *  - `["Nullable", "Maybe"]` will replace `Nullable` with `Maybe` in the type
-   *  - `["${type}[]", ["Nullable", "Maybe"]]` will do both
+   *  - `["colname", "x_colname"]` will replace `colname` with `x_colname` in the type.
+   *  - `["${type}[]", ["colname", x_colname"]]` will do both
    */
   transform: z
     .union([z.string(), z.array(z.union([z.string(), z.tuple([z.string(), z.string()])]))])

packages/eslint-plugin/src/rules/check-sql.test.ts

@@ -123,7 +123,7 @@ RuleTester.describe("check-sql", () => {
         filename,
         options: withConnection(connections.base),
         code: `
-              const result = conn.query<{ id: number; first_name: string; middle_name: Nullable<string>; last_name: string; }>(sql\`
+              const result = conn.query<{ id: number; first_name: string; middle_name: string | null; last_name: string; }>(sql\`
                   select * from caregiver
               \`);
           `,
@@ -148,7 +148,7 @@ RuleTester.describe("check-sql", () => {
         filename,
         options: withConnection(connections.base),
         code: `
-            const result = conn.query<{ caregiver_id: number; agency_id: Nullable<number>; }>(sql\`
+            const result = conn.query<{ caregiver_id: number; agency_id: number | null; }>(sql\`
                 select
                     caregiver.id as caregiver_id,
                     agency.id as agency_id
@@ -352,18 +352,20 @@ RuleTester.describe("check-sql", () => {
         code: "const result = conn.query<{ id: number; }[]>(sql`select id from caregiver`);",
       },
       {
-        name: "transform as [['Nullable', 'Maybe']]",
+        name: "transform as [['middle_name', 'x_middle_name']]",
         filename,
-        options: withConnection(connections.base, { transform: [["Nullable", "Maybe"]] }),
-        code: "const result = conn.query<{ middle_name: Maybe<string>; }>(sql`select middle_name from caregiver`);",
+        options: withConnection(connections.base, {
+          transform: [["middle_name", "x_middle_name"]],
+        }),
+        code: "const result = conn.query<{ x_middle_name: string | null; }>(sql`select middle_name from caregiver`);",
       },
       {
-        name: "transform as ['${type}[]', ['Nullable', 'Maybe']]",
+        name: "transform as ['${type}[]', ['middle_name', 'x_middle_name']]",
         filename,
         options: withConnection(connections.base, {
-          transform: ["${type}[]", ["Nullable", "Maybe"]],
+          transform: ["${type}[]", ["middle_name", "x_middle_name"]],
         }),
-        code: "const result = conn.query<{ middle_name: Maybe<string>; }[]>(sql`select middle_name from caregiver`);",
+        code: "const result = conn.query<{ x_middle_name: string | null; }[]>(sql`select middle_name from caregiver`);",
       },
     ],
     invalid: [],

packages/eslint-plugin/src/rules/check-sql.utils.ts

@@ -26,7 +26,7 @@ function transformType(typeString: string, typeReplacer: TypeTransformer[number]
  * @param transform could be either:
  *  - a string that has ${type} in it,
  *  - an array of tuples that behave as [valueToBeReplaced, typeToReplaceWith]
- *  - an array that has a mix of the above (such as ["${type}[]", ["Nullable", "Maybe"]])
+ *  - an array that has a mix of the above (such as ["${type}[]", ["colname", "x_colname"]])
  */
 export function withTransformType(result: GenerateResult, transform?: TypeTransformer) {
   if (transform === undefined || result.result === null) {

packages/generate/src/generate.test.ts

@@ -123,7 +123,7 @@ test("select with left join should return all cols from left join as nullable",
         FROM caregiver
             LEFT JOIN caregiver_agency ON caregiver.id = caregiver_agency.caregiver_id
     `,
-    expected: `{ caregiver_id: number; assoc_id: Nullable<number>; }`,
+    expected: `{ caregiver_id: number; assoc_id: number | null; }`,
   });
 });
 

packages/generate/src/generate.ts

@@ -166,7 +166,7 @@ function mapColumnAnalysisResultsToTypeLiteral(params: {
 }
 
 function buildInterfacePropertyValue(params: { key: string; value: string; isNullable: boolean }) {
-  return `${params.key}: ${params.isNullable ? `Nullable<${params.value}>` : params.value}`;
+  return `${params.key}: ${params.isNullable ? `${params.value} | null` : params.value}`;
 }
 
 function mapColumnAnalysisResultToPropertySignature(params: {
@@ -178,7 +178,7 @@ function mapColumnAnalysisResultToPropertySignature(params: {
 }) {
   if ("introspected" in params.col) {
     const tsType = params.typesMap[params.col.introspected.colType];
-    const value = params.col.introspected.colNotNull ? tsType : `Nullable<${tsType}>`;
+    const value = params.col.introspected.colNotNull ? tsType : `${tsType} | null`;
     const isFromLeftJoin = params.leftTables.includes(params.col.introspected.tableOid);
     const key = params.col.described.name ?? params.col.introspected.colName;