Deprecation Warning: The `util.isArray` API is deprecated. Please use `Array.isArray()` instead.

[Hari-Shankar-Karthik]

To the devs of connect-flash,

In my nodejs project, I used connect-flash to display messages like 'Comment created successfully', etc. when I got the following warning:

(node:4588) [DEP0044] DeprecationWarning: The util.isArray API is deprecated. Please use Array.isArray() instead.

The stacktrace tells me it originated from connect-flash\lib\flash.js:67:16 when I used node --trace-deprecation

Kindly change it as soon as possible.

Thank you!

[kukielski]

@Hari-Shankar-Karthik
I went into node_modules/connect-flash/lib/flash.js
Then I changed the line: var isArray = require('util').isArray;

to: var isArray = Array.isArray;

I know next to nothing in coding, but now the deprecation error went away for me. Not sure if this is the right solution, as I am still new to all this, but again, I don't have an error any longer.

[ecofi]

+1

[Freezler]

And how do you keep the changes from being overwritten when you delete your lock file and node_modules and do a install again?
Not that it a lot of work to corrwet it but in the spirit of not repeating to much i'm wondering
what could be a solution to this.. I made an .md with my own solution. but it was not well recieved and was told it was solvable in just 2 lines of code.

figured that part out but how do i make the change permanent?

thanks in advance!

[YasharF]

As a temporary workaround you can use a patch file.

1. Add patch-package to your project by npm install patch-package --save.
2. Add "postinstall": "patch-package" to the"scripts" section of your package.json.
3. Create a patches folder in your project and add the following as a file named connect-flash+0.1.1.patch in there.
4. Rerun npm install.

diff --git a/node_modules/connect-flash/lib/flash.js b/node_modules/connect-flash/lib/flash.js
index a278bc1..3870866 100644
--- a/node_modules/connect-flash/lib/flash.js
+++ b/node_modules/connect-flash/lib/flash.js
@@ -2,7 +2,6 @@
  * Module dependencies.
  */
 var format = require('util').format;
-var isArray = require('util').isArray;
 
 
 /**
@@ -64,7 +63,7 @@ function _flash(type, msg) {
     if (arguments.length > 2 && format) {
       var args = Array.prototype.slice.call(arguments, 1);
       msg = format.apply(undefined, args);
-    } else if (isArray(msg)) {
+    } else if (Array.isArray(msg)) {
       msg.forEach(function(val){
         (msgs[type] = msgs[type] || []).push(val);
       });

[rfossella]

Any chance a permanent patch might be coming for this?

[fgirolami29]

🚨 [IMPORTANT NOTICE – Replacement Maintained]

Hey 👋 Just a heads-up for anyone still waiting for updates on connect-flash:

📦 We’ve created a fully compatible, modern, actively maintained fork:
→ @codecorn/connect-flash-new

✅ Supports:

• CommonJS, ESM, and TypeScript
• Safe session management
• Preview middleware for res.locals.sessionFlash
• Future-ready features and security patches

🛠 Maintained by CodeCorn™
📫 Contact: f.girolami@codecorn.it

"We break things beautifully — then we automate the fix."

Feel free to migrate or open issues/PRs directly there.

[YasharF]

@rfossella You can potentially just move off of the dependency with something like:

const { format } = require('util');

const flash = (req, res, next) => {
  if (req.flash) return next();
  req.flash = (type, msg, ...rest) => {
    if (!req.session) throw new Error('req.flash() requires sessions');
    const f = (req.session.flash ||= {});
    if (!type) return (req.session.flash = {}, f);
    if (!msg) return f[type] || [], delete f[type];
    const arr = (f[type] ||= []);
    if (rest.length) arr.push(format(msg, ...rest));
    else if (Array.isArray(msg)) return (arr.push(...msg), arr.length);
    else arr.push(msg);
    return arr;
  };
  res.render = ((r) => function (...a) {
    res.locals.messages = req.flash();
    return r.apply(this, a);
  })(res.render);
  next();
};

app.use(flash);

[rfossella]

This worked well for me. Thank you! Rob From: Federico Girolami ***@***.***> Sent: Saturday, August 2, 2025 11:06 AM To: jaredhanson/connect-flash ***@***.***> Cc: Robert Fossella ***@***.***>; Comment ***@***.***> Subject: Re: [jaredhanson/connect-flash] Deprecation Warning: The `util.isArray` API is deprecated. Please use `Array.isArray()` instead. (Issue #56) <https://avatars.githubusercontent.com/u/68548715?s=20&v=4> fgirolami29 left a comment (jaredhanson/connect-flash#56) <#56 (comment)> 🚨 [IMPORTANT NOTICE – Replacement Maintained] Hey 👋 Just a heads-up for anyone still waiting for updates on <https://www.npmjs.com/package/connect-flash> connect-flash: 📦 We’ve created a fully compatible, modern, actively maintained fork: → ***@***.***/connect-flash-new> @codecorn/connect-flash-new ✅ Supports: * CommonJS, ESM, and TypeScript * Safe session management * Preview middleware for res.locals.sessionFlash * Future-ready features and security patches 🛠 Maintained by CodeCorn™ <https://github.com/codecorn> 📫 Contact: ***@***.*** ***@***.***> "We break things beautifully — then we automate the fix." Feel free to migrate or open issues/PRs directly there. — Reply to this email directly, view it on GitHub <#56 (comment)> , or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAKJUJTQOBVJKS5Y56S27WL3LTHVTAVCNFSM6AAAAABIGW3VV6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTCNBWGU2TKNRRG4> . You are receiving this because you commented. <https://github.com/notifications/beacon/AAKJUJUO7DAH4ZOUIEV7ORD3LTHVTA5CNFSM6AAAAABIGW3VV6WGG33NNVSW45C7OR4XAZNMJFZXG5LFINXW23LFNZ2KUY3PNVWWK3TUL5UWJTV3RSQOC.gif> Message ID: ***@***.*** ***@***.***> >