在 knockout.js 中格式化括号中的负数

Question

如何使用 knockout.js 格式化负百分比并显示在括号中？

function suppressNonNumeric(val,bindingName, allBindingsAccessor) 
{
    return allBindingsAccessor.has(bindingName) && ko.utils.unwrapObservable(allBindingsAccessor.get(bindingName)) && (typeof val === 'undefined' || val === null || isNaN(val));
}

ko.bindingHandlers.percent = {
positions : ko.observable(2),
update : function(element, valueAccessor, allBindingsAccessor) {
    return ko.bindingHandlers.text.update(element, function() {
        var tempVal = ko.utils.unwrapObservable(valueAccessor());
        if(suppressNonNumeric(tempVal,'suppressNull', allBindingsAccessor) )
        {
            return '';
        }
        var value = +(tempVal || 0),
        positions = ko.utils.unwrapObservable(allBindingsAccessor.has('positions') ?    allBindingsAccessor.get('positions') : ko.bindingHandlers.percent.positions);
        return value.toFixed(positions).replace(/(\d)(?=(\d{3})+\.)/g, "$1,") ;
    });

如何修改此函数以检查值是否为负，例如：-23.44 并更改为(23.44)

Answer 1

如果您仍然需要它，我认为以下应该可行：

...
var value = Math.abs(tempVal), // tempVal is defined and is a number, we checked it in suppressNonNumeric
...
return '(' value.toFixed(positions).replace(/(\d)(?=(\d{3})+\.)/g, "$1,") + ')';
...