Preserve out-of-bound writes to stdout/err

Author: webpro

packages/knip/src/ConsoleStreamer.ts

@@ -7,10 +7,13 @@ export class ConsoleStreamer {
   isEnabled = false;
   isWatch = false;
   private lines = 0;
+  private stdoutBaseline = 0;
+  private stderrBaseline = 0;
 
   constructor(options: MainOptions) {
     this.isEnabled = options.isShowProgress;
     this.isWatch = options.isWatch;
+    this.snapshot();
   }
 
   private clearLines(count: number) {
@@ -27,6 +30,18 @@ export class ConsoleStreamer {
     process.stdout.write('\x1b[2J\x1b[1;1f');
   }
 
+  private snapshot() {
+    this.stdoutBaseline = process.stdout.bytesWritten ?? 0;
+    this.stderrBaseline = process.stderr.bytesWritten ?? 0;
+  }
+
+  private hadExternalWrites() {
+    return (
+      (process.stdout.bytesWritten ?? 0) > this.stdoutBaseline ||
+      (process.stderr.bytesWritten ?? 0) > this.stderrBaseline
+    );
+  }
+
   private update(messages: string[]) {
     this.clear();
     process.stdout.write(`${messages.join('\n')}\n`);
@@ -35,13 +50,18 @@ export class ConsoleStreamer {
 
   cast(message: string | string[], sub?: string) {
     if (!this.isEnabled) return;
+    if (this.hadExternalWrites()) this.lines = 0;
     if (Array.isArray(message)) this.update(message);
     else this.update([`${message}${!sub || sub === '.' ? '' : ` (${sub})`}…`]);
+    this.snapshot();
   }
 
   clear() {
     if (!this.isEnabled) return;
+    if (this.hadExternalWrites()) this.lines = 0;
     if (this.isWatch) this.clearScreen();
     else this.clearLines(this.lines);
+    this.lines = 0;
+    this.snapshot();
   }
 }