Sync rules: Export stream SQL functions (#358)

* Sync rules: Export stream SQL functions

* Also patch description

Author: simolus3

.changeset/sixty-knives-thank.md

@@ -0,0 +1,5 @@
+---
+'@powersync/service-sync-rules': patch
+---
+
+Export SQL functions for sync streams.

packages/sync-rules/src/index.ts

@@ -19,6 +19,7 @@ export * from './SqlParameterQuery.js';
 export * from './SqlSyncRules.js';
 export * from './StaticSchema.js';
 export { SyncStream } from './streams/stream.js';
+export { STREAM_FUNCTIONS } from './streams/functions.js';
 export { syncStreamFromSql } from './streams/from_sql.js';
 export * from './TablePattern.js';
 export * from './types.js';

packages/sync-rules/src/request_functions.ts

@@ -107,25 +107,27 @@ export const request_jwt: SqlParameterFunction = {
   usesUnauthenticatedRequestParameters: false
 };
 
-export const request_user_id: SqlParameterFunction = {
-  debugName: 'request.user_id',
-  parameterCount: 0,
-  call(parameters: ParameterValueSet) {
-    return parameters.userId;
-  },
-  getReturnType() {
-    return ExpressionType.TEXT;
-  },
-  detail: 'Authenticated user id',
-  documentation: "The id of the authenticated user.\nSame as `request.jwt() ->> 'sub'`.",
-  usesAuthenticatedRequestParameters: true,
-  usesUnauthenticatedRequestParameters: false
-};
+export function generateUserIdFunction(debugName: string, sameAsDesc: string): SqlParameterFunction {
+  return {
+    debugName,
+    parameterCount: 0,
+    call(parameters: ParameterValueSet) {
+      return parameters.userId;
+    },
+    getReturnType() {
+      return ExpressionType.TEXT;
+    },
+    detail: 'Authenticated user id',
+    documentation: `The id of the authenticated user.\nSame as \`${sameAsDesc} ->> 'sub'\`.`,
+    usesAuthenticatedRequestParameters: true,
+    usesUnauthenticatedRequestParameters: false
+  };
+}
 
 const REQUEST_FUNCTIONS_NAMED = {
   ...globalRequestParameterFunctions('request'),
   jwt: request_jwt,
-  user_id: request_user_id
+  user_id: generateUserIdFunction('request.user_id', 'request.jwt()')
 };
 
 export const REQUEST_FUNCTIONS: Record<string, SqlParameterFunction> = REQUEST_FUNCTIONS_NAMED;

packages/sync-rules/src/sql_functions.ts

@@ -514,7 +514,7 @@ export function generateSqlFunctions(compatibility: CompatibilityContext) {
     SqlFunction['call']
   >;
 
-  const namedRecord: Record<string, SqlFunction> = named;
+  const namedRecord: Record<string, DocumentedSqlFunction> = named;
 
   return {
     named: namedRecord,

packages/sync-rules/src/streams/functions.ts

@@ -1,7 +1,7 @@
 import {
+  generateUserIdFunction,
   globalRequestParameterFunctions,
   parameterFunctions,
-  request_user_id,
   SqlParameterFunction
 } from '../request_functions.js';
 import { ParameterValueSet } from '../types.js';
@@ -27,7 +27,7 @@ export const STREAM_FUNCTIONS: Record<string, Record<string, SqlParameterFunctio
     ...globalRequestParameterFunctions('connection')
   },
   auth: {
-    user_id: request_user_id,
+    user_id: generateUserIdFunction('auth.user_id', 'auth.parameters('),
     ...parameterFunctions({
       schema: 'auth',
       extractJsonString: function (v: ParameterValueSet): string {