From 402fddfe3bcef7ce8b3dd972711a8d038a6f54fc Mon Sep 17 00:00:00 2001
From: Ardis Lu <ardisglu@gmail.com>
Date: Tue, 21 Jan 2025 21:35:38 -0800
Subject: [PATCH] Add graceful failure example

---
 examples/README.md        |  4 +++-
 examples/data/ex9-in.csv  | 11 +++++++++++
 examples/data/ex9-out.csv | 11 +++++++++++
 examples/ex9.js           | 22 ++++++++++++++++++++++
 4 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 examples/data/ex9-in.csv
 create mode 100644 examples/data/ex9-out.csv
 create mode 100644 examples/ex9.js

diff --git a/examples/README.md b/examples/README.md
index 3d97d78..f2000cd 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -24,4 +24,6 @@ node ./examples/ex1.js
 
 [Example 7: Processing rows in batches (multi-row input)](./ex7.js)
 
-[Example 8: Processing rows concurrently (async)](./ex8.js)
\ No newline at end of file
+[Example 8: Processing rows concurrently (async)](./ex8.js)
+
+[Example 9: Handling a flaky transformation (graceful failure)](./ex9.js)
\ No newline at end of file
diff --git a/examples/data/ex9-in.csv b/examples/data/ex9-in.csv
new file mode 100644
index 0000000..9e3c659
--- /dev/null
+++ b/examples/data/ex9-in.csv
@@ -0,0 +1,11 @@
+columnA,columnB
+1,A
+2,B
+3,C
+4,D
+5,E
+6,F
+7,G
+8,H
+9,I
+10,J
diff --git a/examples/data/ex9-out.csv b/examples/data/ex9-out.csv
new file mode 100644
index 0000000..c1979c5
--- /dev/null
+++ b/examples/data/ex9-out.csv
@@ -0,0 +1,11 @@
+columnA,columnB
+1,A
+n/a,n/a
+3,C
+n/a,n/a
+5,E
+n/a,n/a
+7,G
+n/a,n/a
+9,I
+n/a,n/a
diff --git a/examples/ex9.js b/examples/ex9.js
new file mode 100644
index 0000000..1cbfba3
--- /dev/null
+++ b/examples/ex9.js
@@ -0,0 +1,22 @@
+// ## Example 9: Handling a flaky transformation (graceful failure)
+
+import { CSVReader, CSVTransformer, CSVWriter } from '../src/index.js';
+
+// Set a placeholder value and continue processing
+function graceful(row) {
+  return row.map(() => 'n/a');
+}
+
+// Will throw on every other row
+let i = 0;
+function flaky(row) {
+  i++;
+  if (i % 2 === 0) {
+    throw new Error('Example error message');
+  }
+  return row;
+}
+
+await new CSVReader(new URL('./data/ex9-in.csv', import.meta.url))
+  .pipeThrough(new CSVTransformer(flaky, { onError: row => graceful(row) }))
+  .pipeTo(new CSVWriter(new URL('./data/ex9-out.csv', import.meta.url)));
\ No newline at end of file
-- 
2.47.3