globals: introduce prompt on global

.eslintrc.js

@@ -333,5 +333,6 @@ module.exports = {
     btoa: 'readable',
     atob: 'readable',
     performance: 'readable',
+    prompt: 'readable'
   },
 };

doc/api/globals.md

@@ -294,6 +294,26 @@ added: v0.1.7
 
 The process object. See the [`process` object][] section.
 
+## `prompt([message[, defaultValue]])`
+<!-- YAML
+added: REPLACEME
+-->
+
+<!-- type=global -->
+
+* `message` {string} Optional, Message shown to user. Default: `'prompt'`.
+* `defaultValue` {string} Optional, Returned value when user inputs the
+  empty string.
+* Returns: {string|null}
+
+`prompt()` the given message and waits for the user's input.
+If the `stdin` is not interactive, it returns `null`.
+If default value is not given and the user's input is empty string, it also
+returns `null`.
+If default value is given and the user's input is empty string, it returns
+`defaultValue`.
+Otherwise, it returns the user's input as `string`.
+
 ## `queueMicrotask(callback)`
 <!-- YAML
 added: v11.0.0

lib/internal/bootstrap/node.js

@@ -48,6 +48,7 @@ const {
   ObjectSetPrototypeOf,
   ReflectGet,
   ReflectSet,
+  Uint8Array,
   SymbolToStringTag,
   globalThis,
 } = primordials;
@@ -246,6 +247,60 @@ if (!config.noBrowserGlobals) {
     return performance;
   });
 
+  defineOperation(globalThis, 'prompt', function prompt(
+    message = 'prompt',
+    defaultValue
+  ) {
+    const { validateString } = require('internal/validators');
+    validateString(message);
+    if (defaultValue !== undefined) {
+      validateString(defaultValue);
+    }
+
+    defaultValue ??= null;
+    if (!process.stdin.isTTY) {
+      return null;
+    }
+
+    process.stdout.write(message + '\r\n');
+    const res = readFromStdInSync();
+    return res || defaultValue;
+
+    // Mimic implementation of `prompt` of deno
+    function readFromStdInSync() {
+      const fs = require('fs');
+      const LF = '\n'.charCodeAt(0);
+      const CR = '\r'.charCodeAt(0);
+      const charaBuf = new Uint8Array(1);
+      const stdfd = process.platform === 'win32' ?
+        process.stdin.fd :
+        fs.openSync('/dev/tty', 'r');
+      const res = [];
+
+      while (true) {
+        const bytesRead = fs.readSync(stdfd, charaBuf, 0, 1);
+        if (bytesRead === 0) {
+          break;
+        }
+        if (charaBuf[0] === CR) {
+          const bytesRead = fs.readSync(stdfd, charaBuf, 0, 1);
+          if (charaBuf[0] === LF) {
+            break;
+          }
+          res.push(CR);
+          if (bytesRead === 0) {
+            break;
+          }
+        }
+        if (charaBuf[0] === LF) {
+          break;
+        }
+        res.push(charaBuf[0]);
+      }
+      return new TextDecoder().decode(new Uint8Array(res));
+    }
+  });
+
   // Non-standard extensions:
   defineOperation(globalThis, 'clearImmediate', timers.clearImmediate);
   defineOperation(globalThis, 'setImmediate', timers.setImmediate);

test/common/index.js

@@ -291,6 +291,10 @@ if (global.performance) {
   knownGlobals.push(global.performance);
 }
 
+if (global.prompt) {
+  knownGlobals.push(global.prompt);
+}
+
 function allowGlobals(...allowlist) {
   knownGlobals = knownGlobals.concat(allowlist);
 }

test/parallel/test-global.js

@@ -48,6 +48,7 @@ builtinModules.forEach((moduleName) => {
     'clearInterval',
     'clearTimeout',
     'performance',
+    'prompt',
     'setImmediate',
     'setInterval',
     'setTimeout',

test/pseudo-tty/test-prompt.in

@@ -0,0 +1,2 @@
+sushi
+

test/pseudo-tty/test-prompt.js

@@ -0,0 +1,12 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+
+(async () => {
+  const resp1 = prompt('what your favorite food?');
+  assert.strictEqual(resp1, 'sushi');
+
+  const resp2 = prompt('what is the default value?', 'DEFAULT');
+  assert.strictEqual(resp2, 'DEFAULT');
+})().then(common.mustCall(() => {}));

test/pseudo-tty/test-prompt.out

@@ -0,0 +1,3 @@
+sushi
+what your favorite food?
+what is the default value?