TypeError: Cannot read properties of undefined (reading ‘replace’)

/!\ This analysis and fix were generated with Claude Code

WooCommerce 9.9.x + WordPress 6.9 – TypeError: Cannot read properties of undefined (reading ‘replace’) – Root cause and fix

Root cause

The crash happens in the Chart component (components/index.js). The render method destructures itemsLabel from this.props and passes it to sprintf:

const { ..., itemsLabel: b, ... } = this.props;                                                                                                                                        
// ...                                                                                                                                                                                 
totalLabel: (0, y.sprintf)(b, T.length)  

When the Chart is rendered from the Dashboard Charts section (dashboard-charts.js), the parent component (ReportChart) never receives itemsLabel as a prop — it simply isn’t passed.

So b is undefined, and sprintf(undefined, …) crashes on string.replace(…) inside @wordpress/i18n.

This only affects the Dashboard overview. The Analytics report pages (Products, Revenue, etc.) correctly pass itemsLabel, which is why they work fine.

Why patching wp.i18n.sprintf is not straightforward

WordPress’s @wordpress/i18n module uses webpack harmony exports. The sprintf property on wp.i18n is defined via:

Object.defineProperty(exports, "sprintf", { enumerable: true, get: () => sprintf_sprintf });     

This creates a non-configurable getter with no setter. That means:
– wp.i18n.sprintf = myPatchedFn → silently ignored
– Object.defineProperty(wp.i18n, “sprintf”, { value: myFn }) → throws TypeError (non-configurable)

The fix

The solution is to replace the entire window.wp.i18n object with a new one right after wp-i18n loads, but before WooCommerce scripts capture the reference via window[“wp”][“i18n”].

Create a must-use plugin (wp-content/mu-plugins/wc-sprintf-fix.php):

                                                                                                                  

<?php                                                                                                                                                                                  
/**                                                                                                                                                                                    
 * Plugin Name: WooCommerce sprintf Fix                                                                                                                                                
 * Description: Fixes WooCommerce 9.9.x sprintf crash (undefined itemsLabel in dashboard charts).                                                                                      
 * Version: 1.0.0                                                                                                                                                                      
 *                                                                                                                                                                                     
 * @see https://ww.wp.xz.cn/support/topic/typeerror-cannot-read-properties-of-undefined-reading-replace-2/                                                                           
 */                                                                                                                                                                                    

if (!defined('ABSPATH')) {                                                                                                                                                             
    exit;                                                                                                                                                                              
}                                                                                                                                                                                      

add_filter('script_loader_tag', function ($tag, $handle) {                                                                                                                             
    if ($handle !== 'wp-i18n') {                                                                                                                                                       
        return $tag;                                                                                                                                                                   
    }                                                                                                                                                                                  

    $patch = <<<'JS'                                                                                                                                                                   
<script>                                                                                                                                                                               
(function() {                                                                                                                                                                          
    var orig = window.wp.i18n;                                                                                                                                                         
    if (!orig || !orig.sprintf) return;                                                                                                                                                
    var origSprintf = orig.sprintf;                                                                                                                                                    
    var newI18n = {};                                                                                                                                                                  
    var keys = Object.getOwnPropertyNames(orig);                                                                                                                                       
    for (var i = 0; i < keys.length; i++) {                                                                                                                                            
        if (keys[i] === "sprintf") {                                                                                                                                                   
            newI18n.sprintf = function() {                                                                                                                                             
                var a = [].slice.call(arguments);                                                                                                                                      
                if (a[0] == null) a[0] = "";                                                                                                                                           
                return origSprintf.apply(this, a);                                                                                                                                     
            };                                                                                                                                                                         
        } else {                                                                                                                                                                       
            Object.defineProperty(newI18n, keys[i], Object.getOwnPropertyDescriptor(orig, keys[i]));                                                                                   
        }                                                                                                                                                                              
    }                                                                                                                                                                                  
    window.wp.i18n = newI18n;                                                                                                                                                          
})();                                                                                                                                                                                  
</script>                                                                                                                                                                              
JS;                                                                                                                                                                                    

    return $tag . $patch;                                                                                                                                                              
}, 10, 2);                                                                                                                                                                             

                                         

Expected fix from WooCommerce

The proper fix would be for WooCommerce to either:
1. Add itemsLabel to Chart.defaultProps (e.g. itemsLabel: __(‘%d items’, ‘woocommerce’))
2. Or pass itemsLabel from the dashboard charts component to ReportChart

Both fixes are one-liners. Until then, the mu-plugin above works as a safe workaround that can be removed once WooCommerce ships the fix.

Hope this helps others running into this issue!

Note: It’s also possible that this issue is triggered by specific data conditions. In my case (and potentially for other users experiencing this), certain product or order data
configurations in the dashboard charts might cause the itemsLabel prop to not be resolved correctly. If you’re seeing this error intermittently or only with certain date ranges, your data
might be a contributing factor — but the underlying bug remains that sprintf should handle undefined gracefully rather than crashing.

/!\ This analysis and fix were generated with Claude Code