docs(examples): show reading CSV data from a file

examples/scripts/parsing_serializing_csv.ts

@@ -2,16 +2,20 @@
  * @title Parsing and serializing CSV
  * @difficulty beginner
  * @tags cli, deploy, web
- * @run <url>
+ * @run -R main.ts
  * @resource {/examples/import_export} Example: Importing & Exporting
+ * @resource {/examples/reading_files} Example: Reading files
  * @resource {https://datatracker.ietf.org/doc/html/rfc4180} Spec: CSV
  * @group Encoding
  *
  * CSV is a data serialization format that is designed to be portable for table-like applications.
  */
+
+// File: ./main.ts
+
 import { parse, stringify } from "jsr:@std/csv";
 
-// To parse a CSV string, you can use the the standard library's CSV
+// To parse a CSV string, you can use the standard library's CSV
 // parse function. The value is returned as a JavaScript object.
 let text = `
 url,views,likes
@@ -27,6 +31,17 @@ console.log(data[0].url); // https://deno.land
 console.log(data[0].views); // 10
 console.log(data[0].likes); // 7
 
+// If your CSV data is stored in a file, read the file as text before passing
+// it to parse. Run this example with read permission: deno run -R main.ts.
+const fileText = await Deno.readTextFile("./data.csv");
+const fileData = parse(fileText, {
+  skipFirstRow: true,
+  strip: true,
+});
+console.log(fileData[1].url); // https://deno.land/x
+console.log(fileData[1].views); // 20
+console.log(fileData[1].likes); // 15
+
 // In the case where our CSV is formatted differently, we are also able to
 // provide the columns through code.
 text = `
@@ -57,3 +72,10 @@ console.log(csv);
 //- mascot,new
 //- dino,200
 //- bread,2
+
+/* File: ./data.csv
+url,views,likes
+https://deno.land,10,7
+https://deno.land/x,20,15
+https://deno.dev,30,23
+*/