knockout.js Custom Bindings Custom text replace binding
Example
This example is a custom binding that replaces text whenever an input value is updated. In this case, spaces will be replaced with "+". It is intended to be used alongside the existing value binding, and shows binding with an object literal.
Sample markup with the replaceText binding:
<input type="text" data-bind="value: myField, replaceText: {value: myField, find:' ', replace:'+'}" />
Custom binding definition:
ko.bindingHandlers.replaceText = {
//On update, grab the current value and replace text
'update': function(element, valueAccessor, allBindings, viewModel, bindingContext) {
//Get the current value of the input
var val = ko.utils.unwrapObservable(valueAccessor().value());
//Replace text using passed in values obtained from valueAccessor()
//Note - Consider using something like string.js to do the find and replace
var replacedValue = val.split(valueAccessor().find).join(valueAccessor().replace);
//Set new value
valueAccessor().value(replacedValue);
}
}
Sample view model:
var ViewModel = function(){
var self = this;
self.myField = ko.observable("this is a simple test");
}
ko.applyBindings(new ViewModel());
