[英]How do I observe property changes in Polymer 3?
How do I implement continuous checking (time based) of a property-change in a component using an event listener in Polymer 3? 如何使用Polymer 3中的事件监听器对组件中的属性更改进行连续检查(基于时间)?
These are my component's properties: 这些是我组件的属性:
static get properties() {
return {
longitude: {
type: Number
},
latitude: {
type: Number
},
accuracy: {
type: Number
}
};
}
You could use a complex observer that is called whenever any of the specified properties change. 您可以使用一个复杂的观察器 ,只要任何指定的属性发生变化,它都会被调用。 To do this, declare an observers
getter that returns a string array, where each string is the observer method name, followed by a list of dependencies (ie, properties to be observed) in parentheses: 为此,声明一个observers
getter,它返回一个字符串数组,其中每个字符串都是观察者方法名称,其后是括号中的依赖项列表(即要观察的属性):
static get observers() {
return ['_onPropsChanged(longitude, latitude, accuracy)'];
}
_onPropsChanged(longitude, latitude, accuracy) {
console.log({ longitude, latitude, accuracy });
}
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