每当arrayWithDeeplyNestedObjects
发生更改时,我都会尝试调用useEffect()
。export default compose(...
是脱机的第一个数据库的一部分(watermelonDB),并在数据库中有变化时更新arrayWithDeeplyNestedObjects
。可以预期,每当arrayWithDeeplyNestedObjects
变化时,useEffect()
都会执行。但它不是。这是因为useEffect()
只执行shallo比较,不识别arrayWithDeeplyNestedObjects
中的更改。
import withObservables from '@nozbe/with-observables';
import {withDatabase} from '@nozbe/watermelondb/DatabaseProvider';
import {compose} from 'recompose';
import {Q} from '@nozbe/watermelondb';
const Foo = ({arrayWithDeeplyNestedObjects}) => {
console.log('render'); // <-- this renders whenever arrayWithDeeplyNestedObjects is updated
useEffect(() => {
console.log(new Date()); // <-- this does not render whenever arrayWithDeeplyNestedObjects is updated
const doSomething = async () => {
...
};
const data = await doSomething();
setData(data);
}, [arrayWithDeeplyNestedObjects]); // <-- this does only perform a shallow compare
return <SomeNiceUi />
}
export default compose(
withDatabase,
withObservables(['arrayWithDeeplyNestedObjects'], ({database}) => ({
arrayWithDeeplyNestedObjects: database.get(SOME_TABLE).query().observe(),
})),
)(Foo); <-- subscription das fires everytime an update is made to the database
这是arrayWithDeeplyNestedObjects
的外观
[{"__changes": null, "_isEditing": false, "_preparedState": null, "_raw": {"_changed": "x,y", "_status": "created", "id": "3", "x": 5851, "id_arr": "[\"160\"]", "id": "6wmwep5xwfzj3dav", "y": 0.17576194444444446}, "_subscribers": [], "collection": {"_cache": [RecordCache], "_subscribers": [Array], "changes": [Subject], "database": [Database], "modelClass": [Function SomeTable]}}]
对arrayWithDeeplyNestedObjects
的修改是在对x
、y
或id_arr
的对象中完成的。arrayWithDeeplyNestedObjects
的长度也可以改变。那里可能有更多(或更少)相同结构的对象。
如何在每次arrayWithDeeplyNestedObjects
更改时调用useEffect()
?
1条答案
按热度按时间kmpatx3s1#
试试这个: