Use multiple placeholders in validation message.

How to use multiple placeholders inside validation message.

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-debug.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout-validation/2.0.1/knockout.validation.js"></script>
<input type="number" data-bind="textInput: value">

CSS

.validationMessage {
    margin-left: 8px;
    color: #b94a48;
}

.validationElement {
    border-color: #b94a48;
}

JavaScript

ko.validation.init({messagesOnModified: false, decorateElementOnModified: false}, true);

ko.validation.rules.between = {
    validator: function(value, params) {
        var min = params[0];
        var max = params[1];
        
        value = parseInt(value, 10);
        
        if (!isNaN(value)) {
            return value >= min && value <= max;
        }
        return false;   
    },
    message: 'Value must be between {0} and {1}'
};

ko.validation.registerExtenders();

ko.applyBindings({
    value: ko.observable(1).extend({between: [10, 20]})
});