javascript – 具有多个参数的Knockout JS中的扩展程序

可以在knockout.js中使用带有多个参数的 extenders

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' });

但那我怎么把它绑定到可观察的？

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

解决方法

您需要使用一个对象,例如：

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

然后,你会这样称呼它：

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

或者如果您更喜欢更易读的代码：

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