writeプロパティにfunctionを渡すと変更時の処理を書ける。以下の例はpureComputedだけどcomputedも同様。
this.fullName = ko.pureComputed({
read: function () {
return this.firstName() + " " + this.lastName();
},
write: function (value) {
var lastSpacePos = value.lastIndexOf(" ");
if (lastSpacePos > 0) { // Ignore values with no space character
this.firstName(value.substring(0, lastSpacePos)); // Update "firstName"
this.lastName(value.substring(lastSpacePos + 1)); // Update "lastName"
}
},
owner: this
});
参考: