feat: iterator util

Author: subframe7536

README.md

@@ -217,13 +217,18 @@ import {
   exportDatabase,
   importDatabase,
   initSQLiteCore,
+  iterator,
   run,
 } from '@subframe7536/sqlite-wasm'
 
 const core = await initSQLiteCore(/* options */)
 
 await importDatabase(core.vfs, core.path, stream)
 
+for await (const row of iterator(core, 'select * from test')) {
+  console.log(row)
+}
+
 customFunctionCore(core, 'test', num => num)
 await run(core, 'select test(?)', [1])
 

playground/src/index.ts

@@ -119,7 +119,7 @@ document.querySelector('.worker')?.addEventListener('click', async () => {
   }
   worker.postMessage('')
   for await (const data of test()) {
-    console.log('iterator', data)
+    console.log('[stream]', data)
   }
 })
 document.querySelector('.importW')?.addEventListener('click', async () => {

playground/src/runSQL.ts

@@ -1,3 +1,5 @@
+import { iterator, type SQLiteDBCore } from '../../src'
+
 export async function runSQL(run: (sql: string, parameters?: any[]) => Promise<any>): Promise<void> {
   await run('CREATE TABLE if not exists t1(a INTEGER, b INTEGER, c VARCHAR);')
   await run('INSERT INTO t1 VALUES(1, 19147, \'nineteen thousand one hundred forty-seven\');')
@@ -16,3 +18,13 @@ export async function runSQLStream(
   await run('INSERT INTO t1 VALUES(3, 46582, \'forty-six thousand five hundred eighty-two\');')
   await stream(onData, 'select * from t1')
 }
+
+export async function runIterator(
+  core: SQLiteDBCore,
+): Promise<void> {
+  const sql = 'INSERT INTO t1 VALUES(100, 19147, \'nineteen thousand one hundred forty-seven\'), (200, 26008, \'twenty-six thousand eight\'), (300, 46582, \'forty-six thousand five hundred eighty-two\');select * from t1;'
+  const it = iterator(core, sql)
+  for await (const row of it) {
+    console.log('[iterator]', row)
+  }
+}

playground/src/worker.ts

@@ -1,8 +1,8 @@
 import { uuidv7 } from 'uuidv7'
 import url from '../../dist/wa-sqlite.wasm?url'
-import { customFunction, initSQLite, isOpfsSupported, withExistDB } from '../../src'
+import { customFunction, initSQLite, isOpfsSupported, iterator, withExistDB } from '../../src'
 import { useOpfsStorage } from '../../src/vfs/opfs'
-import { runSQLStream } from './runSQL'
+import { runIterator, runSQLStream } from './runSQL'
 
 onmessage = async ({ data }) => {
   if (!await isOpfsSupported()) {
@@ -17,10 +17,12 @@ onmessage = async ({ data }) => {
     postMessage(await db.dump())
     return
   }
+
   // if (data) {
   //   await db.sync(data)
   // }
   await runSQLStream(db.run, db.stream, data => postMessage(data))
+  await runIterator(db)
   console.log(db.lastInsertRowId(), db.changes())
   customFunction(db.sqlite, db.pointer, 'uuidv7', () => uuidv7())
   console.log(

src/utils.ts

@@ -220,3 +220,21 @@ export async function run(
   await stream(core, data => results.push(data), sql, parameters)
   return results
 }
+
+export async function* iterator(
+  core: SQLiteDBCore,
+  sql: string,
+  parameters?: SQLiteCompatibleType[],
+): AsyncIterableIterator<Record<string, SQLiteCompatibleType>> {
+  const { sqlite, pointer } = core
+  for await (const stmt of sqlite.statements(pointer, sql)) {
+    if (parameters?.length) {
+      sqlite.bind_collection(stmt, parameters)
+    }
+    const cols = sqlite.column_names(stmt)
+    while (await sqlite.step(stmt) === SQLITE_ROW) {
+      const row = sqlite.row(stmt)
+      yield Object.fromEntries(cols.map((key, i) => [key, row[i]]))
+    }
+  }
+}