Custom Filters

Syntax#

Vue.filter(name, function(value){}); //Basic
Vue.filter(name, function(value, begin, end){}); //Basic with wrapping values
Vue.filter(name, function(value, input){}); //Dynamic
Vue.filter(name, { read: function(value){}, write: function(value){} }); //Two-way

Parameters#

Parameter	Details
name	String - desired callable name of the filter
value	[Callback] Any - value of the data passing into the filter
begin	[Callback] Any - value to come before the passed data
end	[Callback] Any - value to come after the passed data
input	[Callback] Any - user input bound to Vue instance for dynamic results
## Two-way Filters
With a `two-way filter`, we are able to assign a `read` and `write` operation for a single `filter` that changes the value of the same data between the `view` and `model`.

//JS
Vue.filter('uppercase', {
    //read : model -> view
    read: function(value) {
        return value.toUpperCase();
    },

    //write : view -> model
    write: function(value) {
        return value.toLowerCase();
    }
});

/*
 * Base value of data: 'example string'
 *
 * In the view : 'EXAMPLE STRING'
 * In the model : 'example string'
 */

Basic

Custom filters in Vue.js can be created easily in a single function call to Vue.filter.

//JS
Vue.filter('reverse', function(value) {
    return value.split('').reverse().join('');
});

//HTML
<span>{{ msg | reverse }}</span> //'This is fun!' => '!nuf si sihT'

It is good practice to store all custom filters in separate files e.g. under ./filters as it is then easy to re-use your code in your next application. If you go this way you have to replace JS part:

//JS
Vue.filter('reverse', require('./filters/reverse'));

You can also define your own begin and end wrappers as well.

//JS
Vue.filter('wrap', function(value, begin, end) {
    return begin + value + end;
});

//HTML
<span>{{ msg | wrap 'The' 'fox' }}</span> //'quick brown' => 'The quick brown fox'