javascript - 具有多个参数的 Knockout JS 中的扩展器

Question

一个可以使用extenders在 knockout.js 中有多个参数

示例:

ko.extenders.currency = function(target, currencySymbol, position) {
    var result = ko.computed({
        read: target,  
        write: function(newValue) {
            var current = target(),
            if (position == 'left') {
                target(currencySymbol+target);
            } else {
                target(target+currencySymbol);
            }
        }
    }).extend({ notify: 'always' });

但是我如何将它绑定(bind)到 observable？

this.One = ko.observable(one).extend({ currency: ???, currencySymbol: '£', position : 'left'});

Answer 1

你需要为此使用一个对象，例如:

ko.extenders.currency = function(target, options) {
    var currencySymbol = options.symbol,
        position = options.position;
    var result = ko.computed({
        read: target,  
        write: function(newValue) {
            var current = target(),
            if (position == 'left') {
                target(currencySymbol+target);
            } else {
                target(target+currencySymbol);
            }
        }
    }).extend({ notify: 'always' });

然后，您可以这样调用它:

this.One = ko.observable(one).extend({ currency: { symbol: '£', position : 'left' } });

或者如果您更喜欢可读性更强的代码:

var currencyOptions = { symbol: '£', position: 'left' };
this.One = ko.observable(one).extend({ currency: currencyOptions });