[英]Accept decimal places in KO numeric extension
我已经实现了 Knockout live 1 示例中显示的扩展器 - https://knockoutjs.com/documentation/extenders.html
ko.extenders.precision = function (target, precision) {
//create a writable computed observable to intercept writes to our observable
var result = ko
.pureComputed({
read: target, //always return the original observables value
write: function (newValue) {
var current = target(),
roundingMultiplier = Math.pow(10, precision),
newValueAsNum = isNaN(newValue) ? 0 : +newValue,
valueToWrite =
Math.round(newValueAsNum * roundingMultiplier) / roundingMultiplier;
//only write if it changed
if (valueToWrite !== current) {
target(valueToWrite);
} else {
//if the rounded value is the same, but a different value was written, force a notification for the current field
if (newValue !== current) {
target.notifySubscribers(valueToWrite);
}
}
},
})
.extend({ notify: "always" });
//initialize with current value to make sure it is rounded appropriately
result(target());
//return the new computed observable
return result;
};
model视图如下:
model.gwaioDifficultySettings = {
minionMod: ko.observable(0).extend({
precision: 3,
rateLimit: { timeout: 500, method: "notifyWhenChangesStop" },
}),
};
它可以通过 HTML 输入字段访问:
<div>
<input
type="number"
style="width: 50px; padding-bottom: 0px;"
data-bind="textInput: model.gwaioDifficultySettings.minionMod"
/>
<span style="margin-left: 6px;"></span>
<loc>Minion Modifier</loc>
<span
class="info_tip"
data-bind="tooltip: '!LOC:Mandatory Minions + Star Distance * Minion Modifier = number of additional enemy Commanders.'"
>?</span
>
</div>
但是,我必须添加rateLimit: { timeout: 500, method: "notifyWhenChangesStop" }
,否则我发现一旦值为 integer,该字段将删除小数点,然后它将阻止任何尝试输入又是小数点。
在实际示例中似乎并非如此,我想知道我哪里出错了,或者仅仅是因为我使用 Knockout 3 和 Chromium 28 的环境。
我将https://gist.github.com/gnab/7579584中的一些代码添加到我的扩展器中:
if (_.isString(newValue)) {
newValue = newValue.replace(",", ".");
newValue = parseFloat(newValue);
if (!isNaN(newValue)) {
target(newValue);
}
}
这导致:
ko.extenders.precision = function (target, precision) {
//create a writable computed observable to intercept writes to our observable
var result = ko
.pureComputed({
read: target, //always return the original observables value
write: function (newValue) {
if (_.isString(newValue)) {
newValue = newValue.replace(",", ".");
newValue = parseFloat(newValue);
if (!isNaN(newValue)) {
target(newValue);
}
}
var current = target(),
roundingMultiplier = Math.pow(10, precision),
newValueAsNum = isNaN(newValue) ? 0 : +newValue,
valueToWrite =
Math.round(newValueAsNum * roundingMultiplier) / roundingMultiplier;
//only write if it changed
if (valueToWrite !== current) {
target(valueToWrite);
} else {
//if the rounded value is the same, but a different value was written, force a notification for the current field
if (newValue !== current) {
target.notifySubscribers(valueToWrite);
}
}
},
})
.extend({ notify: "always" });
//initialize with current value to make sure it is rounded appropriately
result(target());
//return the new computed observable
return result;
};
到目前为止,在我所有的测试中,这似乎都按要求执行。 如果输入一个小数点,它会留下一个可见的悬挂小数点,但这似乎不会产生任何负面影响。
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