doc: add esm examples to node:readline

mfdebian · ruyadorno · commit d6a84cf781e4 · 2025-01-05T13:05:31.000-05:00
PR-URL: #55335 Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
diff --git a/doc/api/readline.md b/doc/api/readline.md
@@ -703,9 +703,18 @@ added: v17.0.0
 The `readlinePromises.createInterface()` method creates a new `readlinePromises.Interface`
 instance.
 
-```js
-const readlinePromises = require('node:readline/promises');
-const rl = readlinePromises.createInterface({
+```mjs
+import { createInterface } from 'node:readline/promises';
+import { stdin, stdout } from 'node:process';
+const rl = createInterface({
+  input: stdin,
+  output: stdout,
+});
+```
+
+```cjs
+const { createInterface } = require('node:readline/promises');
+const rl = createInterface({
   input: process.stdin,
   output: process.stdout,
 });
@@ -960,9 +969,18 @@ changes:
 The `readline.createInterface()` method creates a new `readline.Interface`
 instance.
 
-```js
-const readline = require('node:readline');
-const rl = readline.createInterface({
+```mjs
+import { createInterface } from 'node:readline';
+import { stdin, stdout } from 'node:process';
+const rl = createInterface({
+  input: stdin,
+  output: stdout,
+});
+```
+
+```cjs
+const { createInterface } = require('node:readline');
+const rl = createInterface({
   input: process.stdin,
   output: process.stdout,
 });
@@ -1098,9 +1116,36 @@ if (process.stdin.isTTY)
 The following example illustrates the use of `readline.Interface` class to
 implement a small command-line interface:
 
-```js
-const readline = require('node:readline');
-const rl = readline.createInterface({
+```mjs
+import { createInterface } from 'node:readline';
+import { exit, stdin, stdout } from 'node:process';
+const rl = createInterface({
+  input: stdin,
+  output: stdout,
+  prompt: 'OHAI> ',
+});
+
+rl.prompt();
+
+rl.on('line', (line) => {
+  switch (line.trim()) {
+    case 'hello':
+      console.log('world!');
+      break;
+    default:
+      console.log(`Say what? I might have heard '${line.trim()}'`);
+      break;
+  }
+  rl.prompt();
+}).on('close', () => {
+  console.log('Have a great day!');
+  exit(0);
+});
+```
+
+```cjs
+const { createInterface } = require('node:readline');
+const rl = createInterface({
   input: process.stdin,
   output: process.stdout,
   prompt: 'OHAI> ',
@@ -1130,14 +1175,37 @@ A common use case for `readline` is to consume an input file one line at a
 time. The easiest way to do so is leveraging the [`fs.ReadStream`][] API as
 well as a `for await...of` loop:
 
-```js
-const fs = require('node:fs');
-const readline = require('node:readline');
+```mjs
+import { createReadStream } from 'node:fs';
+import { createInterface } from 'node:readline';
 
 async function processLineByLine() {
-  const fileStream = fs.createReadStream('input.txt');
+  const fileStream = createReadStream('input.txt');
 
-  const rl = readline.createInterface({
+  const rl = createInterface({
+    input: fileStream,
+    crlfDelay: Infinity,
+  });
+  // Note: we use the crlfDelay option to recognize all instances of CR LF
+  // ('\r\n') in input.txt as a single line break.
+
+  for await (const line of rl) {
+    // Each line in input.txt will be successively available here as `line`.
+    console.log(`Line from file: ${line}`);
+  }
+}
+
+processLineByLine();
+```
+
+```cjs
+const { createReadStream } = require('node:fs');
+const { createInterface } = require('node:readline');
+
+async function processLineByLine() {
+  const fileStream = createReadStream('input.txt');
+
+  const rl = createInterface({
     input: fileStream,
     crlfDelay: Infinity,
   });
@@ -1155,12 +1223,26 @@ processLineByLine();
 
 Alternatively, one could use the [`'line'`][] event:
 
-```js
-const fs = require('node:fs');
-const readline = require('node:readline');
+```mjs
+import { createReadStream } from 'node:fs';
+import { createInterface } from 'node:readline';
 
-const rl = readline.createInterface({
-  input: fs.createReadStream('sample.txt'),
+const rl = createInterface({
+  input: createReadStream('sample.txt'),
+  crlfDelay: Infinity,
+});
+
+rl.on('line', (line) => {
+  console.log(`Line from file: ${line}`);
+});
+```
+
+```cjs
+const { createReadStream } = require('node:fs');
+const { createInterface } = require('node:readline');
+
+const rl = createInterface({
+  input: createReadStream('sample.txt'),
   crlfDelay: Infinity,
 });
 
@@ -1172,7 +1254,32 @@ rl.on('line', (line) => {
 Currently, `for await...of` loop can be a bit slower. If `async` / `await`
 flow and speed are both essential, a mixed approach can be applied:
 
-```js
+```mjs
+import { once } from 'node:events';
+import { createReadStream } from 'node:fs';
+import { createInterface } from 'node:readline';
+
+(async function processLineByLine() {
+  try {
+    const rl = createInterface({
+      input: createReadStream('big-file.txt'),
+      crlfDelay: Infinity,
+    });
+
+    rl.on('line', (line) => {
+      // Process the line.
+    });
+
+    await once(rl, 'close');
+
+    console.log('File processed.');
+  } catch (err) {
+    console.error(err);
+  }
+})();
+```
+
+```cjs
 const { once } = require('node:events');
 const { createReadStream } = require('node:fs');
 const { createInterface } = require('node:readline');
