doc: adds usage of readline line-by-line parsing

In order to make developers aware of node-core built-in functionality, which might replace module APIs, we should add an example of readline`s interface usage. SEO will eventually aid this goal, since it is well searched on Q&A sites. PR-URL: #4609 Reviewed-By: Roman Reiss <me@silverwind.io> Reviewed-By: James M Snell <jasnell@gmail.com>>
nodejs · Jan 12, 2016 · 3912b5c · 3912b5c
1 parent 787c5d9
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diff --git a/doc/api/readline.markdown b/doc/api/readline.markdown
@@ -232,6 +232,22 @@ line interface:
       process.exit(0);
     });
 
+## Example: Read File Stream Line-by-Line
+
+A common case for `readline`'s `input` option is to pass a filesystem readable
+stream to it. This is how one could craft line-by-line parsing of a file:
+
+    const readline = require('readline');
+    const fs = require('fs');
+
+    const rl = readline.createInterface({
+      input: fs.createReadStream('sample.txt')
+    });
+
+    rl.on('line', function (line) {
+      console.log('Line from file:', line);
+    });
+
 ## readline.clearLine(stream, dir)
 
 Clears current line of given TTY stream in a specified direction.