add duckdb-ui-client & other ts pkgs (#10)

* add duckdb-ui-client & other ts pkgs

* workflow fixes

* fix working dir

* no sparse checkout; specify package.json path

* path to pnpm-lock.yaml

* add check & build test

* workflow step descriptions

* use comments & names

* one more naming tweak

ts/pkgs/duckdb-ui-client/src/client/classes/DuckDBUIClient.ts

@@ -0,0 +1,72 @@
+import { sendDuckDBUIHttpRequest } from '../../http/functions/sendDuckDBUIHttpRequest.js';
+import { tokenizeResultFromBuffer } from '../../serialization/functions/tokenizeResultFromBuffer.js';
+import type { TokenizeResult } from '../../serialization/types/TokenizeResult.js';
+import { DuckDBUIClientConnection } from './DuckDBUIClientConnection.js';
+
+export { DuckDBUIClientConnection };
+export type { TokenizeResult };
+
+export class DuckDBUIClient {
+  private readonly eventSource: EventSource;
+
+  private defaultConnection: DuckDBUIClientConnection | undefined;
+
+  private constructor() {
+    this.eventSource = new EventSource('/localEvents');
+  }
+
+  public addOpenEventListener(listener: (event: Event) => void) {
+    this.eventSource.addEventListener('open', listener);
+  }
+
+  public removeOpenEventListener(listener: (event: Event) => void) {
+    this.eventSource.removeEventListener('open', listener);
+  }
+
+  public addErrorEventListener(listener: (event: Event) => void) {
+    this.eventSource.addEventListener('error', listener);
+  }
+
+  public removeErrorEventListener(listener: (event: Event) => void) {
+    this.eventSource.removeEventListener('error', listener);
+  }
+
+  public addMessageEventListener(
+    type: string,
+    listener: (event: MessageEvent) => void,
+  ) {
+    this.eventSource.addEventListener(type, listener);
+  }
+
+  public removeMessageEventListener(
+    type: string,
+    listener: (event: MessageEvent) => void,
+  ) {
+    this.eventSource.removeEventListener(type, listener);
+  }
+
+  public connect() {
+    return new DuckDBUIClientConnection();
+  }
+
+  public get connection(): DuckDBUIClientConnection {
+    if (!this.defaultConnection) {
+      this.defaultConnection = this.connect();
+    }
+    return this.defaultConnection;
+  }
+
+  public async tokenize(text: string): Promise<TokenizeResult> {
+    const buffer = await sendDuckDBUIHttpRequest('/ddb/tokenize', text);
+    return tokenizeResultFromBuffer(buffer);
+  }
+
+  private static singletonInstance: DuckDBUIClient;
+
+  public static get singleton(): DuckDBUIClient {
+    if (!DuckDBUIClient.singletonInstance) {
+      DuckDBUIClient.singletonInstance = new DuckDBUIClient();
+    }
+    return DuckDBUIClient.singletonInstance;
+  }
+}