From 25d3d6649230770d53f00d7878de217850b3bd2f Mon Sep 17 00:00:00 2001
From: d-llama <132324914+d-llama@users.noreply.github.com>
Date: Mon, 22 May 2023 22:04:25 -0700
Subject: [PATCH] Add the ability to flush() the LogSink from OptionalLogger
 and friends (#19)

---
 package.json       | 2 +-
 src/logger.test.ts | 9 +++++++++
 src/logger.ts      | 4 ++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/package.json b/package.json
index 9743b58..d1f7ecc 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@rocicorp/logger",
   "description": "Logging utilities",
-  "version": "5.0.0",
+  "version": "5.1.0",
   "repository": "github:rocicorp/logger",
   "license": "Apache-2.0",
   "engines": {
diff --git a/src/logger.test.ts b/src/logger.test.ts
index e789757..56576c8 100644
--- a/src/logger.test.ts
+++ b/src/logger.test.ts
@@ -262,6 +262,15 @@ test('tee logger flush', async () => {
   expect(l3.flushCount).to.equal(1);
 });
 
+test('optional logger flush', async () => {
+  const l1 = new TestLogSinkWithFlush();
+  const logger = new OptionalLoggerImpl(l1);
+
+  expect(l1.flushCount).to.equal(0);
+  await logger.flush();
+  expect(l1.flushCount).to.equal(1);
+});
+
 test('Console logger calls JSON stringify on complex arguments', () => {
   const jsonStringifySpy = sinon.spy(JSON, 'stringify');
   const mockDebug = mockConsoleMethod('debug');
diff --git a/src/logger.ts b/src/logger.ts
index 93223ff..417b2cd 100644
--- a/src/logger.ts
+++ b/src/logger.ts
@@ -9,6 +9,7 @@ export interface OptionalLogger {
   error?(...args: unknown[]): void;
   info?(...args: unknown[]): void;
   debug?(...args: unknown[]): void;
+  flush?(): Promise<void>;
 }
 
 /**
@@ -59,6 +60,7 @@ export class OptionalLoggerImpl implements OptionalLogger {
   readonly debug?: (...args: unknown[]) => void = undefined;
   readonly info?: (...args: unknown[]) => void = undefined;
   readonly error?: (...args: unknown[]) => void = undefined;
+  readonly flush: () => Promise<void>;
 
   constructor(logSink: LogSink, level: LogLevel = 'info', context?: Context) {
     const impl =
@@ -78,6 +80,8 @@ export class OptionalLoggerImpl implements OptionalLogger {
         this.error = impl('error');
     }
     /* eslint-enable @typescript-eslint/ban-ts-comment, no-fallthrough */
+
+    this.flush = () => logSink.flush?.() ?? Promise.resolve();
   }
 }