ignoreElements
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2023-12-01
ignoreElements
函数签名: ignoreElements(): Observable
忽略所有通知,除了 complete 和 error 。
示例
示例 1: 忽略源 observable 的所有数据项
( StackBlitz | jsBin | jsFiddle )
// RxJS v6+
import { interval } from 'rxjs';
import { take, ignoreElements } from 'rxjs/operators';
// 每100毫秒发出值
const source = interval(100);
// 略所有值,只发出 complete
const example = source.pipe(
take(5),
ignoreElements()
);
// 输出: "COMPLETE!"
const subscribe = example.subscribe(
val => console.log(`NEXT: ${val}`),
val => console.log(`ERROR: ${val}`),
() => console.log('COMPLETE!')
);
示例 2: 只显示错误
( StackBlitz | jsBin | jsFiddle )
// RxJS v6+
import { interval, throwError, of } from 'rxjs';
import { mergeMap, ignoreElements } from 'rxjs/operators';
// 每100毫秒发出值
const source = interval(100);
// 忽略所有值,只发出 error
const error = source.pipe(
mergeMap(val => {
if (val === 4) {
return throwError(`ERROR AT ${val}`);
}
return of(val);
}),
ignoreElements()
);
// 输出: "ERROR: ERROR AT 4"
const subscribe = error.subscribe(
val => console.log(`NEXT: ${val}`),
val => console.log(`ERROR: ${val}`),
() => console.log('SECOND COMPLETE!')
);
其他资源
- ignoreElements :newspaper: - 官方文档
源码: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/ignoreElements.ts