Title: Javascript error with sprintf
Last modified: January 8, 2025

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# Javascript error with sprintf

 *  Resolved [therealgilles](https://wordpress.org/support/users/chamois_blanc/)
 * (@chamois_blanc)
 * [1 year, 5 months ago](https://wordpress.org/support/topic/javascript-error-with-sprintf/)
 * I am seeing the following javascript error related to `sprintf` on a Post admin
   edit page:
 * [https://ibb.co/pQz15xt](https://ibb.co/pQz15xt)
 * Is Pods using `window.sprintf`? I see a `sprintf.min.js` asset under `pods/ui`.
   Plugins should not be using anything attached to `window` that is not browser
   native.
    -  This topic was modified 1 year, 5 months ago by [therealgilles](https://wordpress.org/support/users/chamois_blanc/).
    -  This topic was modified 1 year, 5 months ago by [therealgilles](https://wordpress.org/support/users/chamois_blanc/).

Viewing 4 replies - 1 through 4 (of 4 total)

 *  Plugin Support [pdclark](https://wordpress.org/support/users/pdclark/)
 * (@pdclark)
 * [1 year, 4 months ago](https://wordpress.org/support/topic/javascript-error-with-sprintf/#post-18238719)
 * The error message says `syntax error [sprintf] unexpected placeholder`.
 * This error means that `sprintf` was passed more placeholders prefixed with `%`
   than it expected compared to the number of values provided to fill those placeholders.
 * This means the computer was asked to do something that is physically and mathematically
   impossible: e.g., fill 3 empty buckets with 2 explicit things.
 * This error usually happens when a human passes `%` to sprintf, not realizing 
   that `%%` must be used for a literal percentage mark, because `%` is reserved
   for denoting a placeholder in `sprintf` templates.
 * “Should” is a subjective opinion, not a computer error — the error is regarding
   sprintf template requirements; doesn’t have anything to do with the window object.
 * Computers are like [Mr. Miyagi’s frog](https://youtu.be/Y3lQSxNdr3c?t=11): they
   either do correctly, do not at all, or do the incorrect thing correctly.
 *  Thread Starter [therealgilles](https://wordpress.org/support/users/chamois_blanc/)
 * (@chamois_blanc)
 * [1 year, 4 months ago](https://wordpress.org/support/topic/javascript-error-with-sprintf/#post-18240984)
 * Hi [@pdclark](https://wordpress.org/support/users/pdclark/),
 *  Thank you for your response. In theory you are right now but there is so much
   more that could go wrong. As you know, the JS `window` object is shared between
   all JS scripts, therefore there is no guarantee what `window.sprintf` is. Another
   script could be doing something like this:
 *     ```wp-block-code
       window.sprintf = ('my-sprintf', str, ...args) => someLibrarySprintf(str, ...args);
       ```
   
 * or even this:
 *     ```wp-block-code
       window.sprintf = 1;
       ```
   
 * In a shared environment, one cannot predict if another plugin is going to alter
   a shared function. Best practice advises not to rely on shared objects and use
   scope that you can define and control. JS bundlers do this really well.
 * If `pods/ui` does not (re-)define `window.sprintf`, then the placeholder error
   would not point to the `pods` plugin and it would likely instead point to the
   version of faulty plugin. Right now, `pods` is obscuring the real issue, which
   is not helpful and could be avoided. At least, that’s my observation.
 *  Plugin Support [pdclark](https://wordpress.org/support/users/pdclark/)
 * (@pdclark)
 * [1 year, 4 months ago](https://wordpress.org/support/topic/javascript-error-with-sprintf/#post-18243665)
 * We would be more than happy to help resolve what template-variable mismatch was
   passed to `sprintf`, causing the reported error. The best place for that technical
   discussion will likely be a GitHub issue submitted via [https://pods.io/submit](https://pods.io/submit)
 * The error from `sprintf` usually indicates a mismatch between the number of placeholders
   versus the number of variables passed to the function, so details about the templates,
   context, and Pods configuration in use will be beneficial in tracking down the
   cause, especially if the page or fields contain the `%` character.
 * As for preferences of function scopes and naming conventions, you can certainly
   submit an additional ticket to that effect. It may be beneficial to consider 
   that in the context of a [polyfill](https://www.geeksforgeeks.org/what-is-a-polyfill/),`
   sprintf` is a function first defined in C, a 53-year-old programming language.
 * When a feature of one language or environment is ported to another, it is typically
   referred to as a [polyfill](https://www.geeksforgeeks.org/what-is-a-polyfill/).
   For example, [PHP.js](https://github.com/hirak/phpjs), which ports many PHP convenience
   functions to JavaScript, scoped to a `php` object.
 * You are correct that JavaScript scope is an important consideration. However,
   it is not for security reasons, but to avoid confusion.
 * JavaScript by definition is a language which can redefine itself:
 * Just as any authorized script in an application can call `window.sprintf = 1;`,
   one can also call `window.php.sprintf = 2;` or `Array.prototype = Hacked();` —
   the last of which would redefine the definition of a core data structure to any
   arbitrary behavior for all scripts of all scopes.
 * This is how JavaScript is architected. Naming conventions do not prevent this,
   rather, browser sandboxes and cross-domain security restrictions do.
 * It is true that scoping variables with discretion can avoid developer confusion.
   If `sprintf()` is defined in the global scope, it was likely done with the understanding
   that `sprintf` is a function which has been understood to follow a certain format
   in the global scope across many programming language for more than 50 years.
 * A similar functionality added in recent core JavaScript versions would be the
   tilde string marker, which provides a shorthand for similar string template functionality
   with a more lenient standard for data validation than sprintf.
 *  Thread Starter [therealgilles](https://wordpress.org/support/users/chamois_blanc/)
 * (@chamois_blanc)
 * [1 year, 4 months ago](https://wordpress.org/support/topic/javascript-error-with-sprintf/#post-18244501)
 * As expected, the problematic template string was from another plugin. I already
   filled a separate issue for it.
 * A library such as PHP.js or [https://github.com/alexei/sprintf.js](https://github.com/alexei/sprintf.js)
   is not a polyfill. From [https://developer.mozilla.org/en-US/docs/Glossary/Polyfill](https://developer.mozilla.org/en-US/docs/Glossary/Polyfill):
 *     ```wp-block-code
       A polyfill is a piece of code (usually JavaScript on the Web) used to provide modern functionality on older browsers that do not natively support it.
       ```
   
 * About sprintf in C (and other languages), it’s been modified as recently as 202x
   due to problems with typing (see [https://en.wikipedia.org/wiki/Printf](https://en.wikipedia.org/wiki/Printf)),
   so yes it’s been mostly stable but there are still possibilities of mismatches.
   Even the JS sprintf library above was last modified 2 years ago.
 * My larger point is that in an ecosystem such as WordPress, each (plugin) developer
   should do their best to avoid creating conflicts with other plugins. This will
   make both the users’ and the developer’s life easier in the long term. I understand
   things were wild in 2006 (when jQuery was first introduced) but 19 years later,
   using private scope should be the norm.
 * There are already plenty of issues arising from different plugins using different
   versions of composer packages in PHP. We don’t need more of that in JS.
 * You’re mentioning a tilde string marker but I don’t see anything like this in
   the JS core. Are you referring to the bitwise operator used with strings (like`
   ~str.indexOf(...)`?).
 * Anyway I won’t file a separate issue about scoping, I hope I got my point across.
   Whether you want to act on it or not is up to you. I’ll keep the github link 
   in mind for the future.
    -  This reply was modified 1 year, 4 months ago by [therealgilles](https://wordpress.org/support/users/chamois_blanc/).
    -  This reply was modified 1 year, 4 months ago by [therealgilles](https://wordpress.org/support/users/chamois_blanc/).

Viewing 4 replies - 1 through 4 (of 4 total)

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 * 4 replies
 * 2 participants
 * Last reply from: [therealgilles](https://wordpress.org/support/users/chamois_blanc/)
 * Last activity: [1 year, 4 months ago](https://wordpress.org/support/topic/javascript-error-with-sprintf/#post-18244501)
 * Status: resolved