本文整理汇总了TypeScript中rxjs/operators.defaultIfEmpty函数的典型用法代码示例。如果您正苦于以下问题：TypeScript defaultIfEmpty函数的具体用法？TypeScript defaultIfEmpty怎么用？TypeScript defaultIfEmpty使用的例子？那么恭喜您, 这里精选的函数代码示例或许可以为您提供帮助。
在下文中一共展示了defaultIfEmpty函数的8个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于我们的系统推荐出更棒的TypeScript代码示例。
示例1: rule
return input.pipe(mergeMap(inputTree => {
const result = rule(inputTree, context);
if (!result) {
return observableOf(inputTree);
} else if (typeof result == 'function') {
// This is considered a Rule, chain the rule and return its output.
return callRule(result, observableOf(inputTree), context);
} else if (isObservable(result)) {
// Only return the last Tree, and make sure it's a Tree.
return result.pipe(
defaultIfEmpty(),
last(),
tap(inner => {
if (!inner || !(TreeSymbol in inner)) {
throw new InvalidRuleResultException(inner);
}
}),
);
} else if (TreeSymbol in result) {
return observableOf(result);
} else {
return throwError(new InvalidRuleResultException(result));
}
}));
开发者ID:DevIntent，项目名称:angular-cli，代码行数:25，代码来源:call.ts
示例2: getNpmConfigOption
function getNpmConfigOption(
option: string,
scope?: string,
tryWithoutScope?: boolean,
): Observable<string | undefined> {
if (scope && tryWithoutScope) {
return concat(
getNpmConfigOption(option, scope),
getNpmConfigOption(option),
).pipe(
filter(result => !!result),
defaultIfEmpty(),
first(),
);
}
const fullOption = `${scope ? scope + ':' : ''}${option}`;
let value = npmConfigOptionCache.get(fullOption);
if (value) {
return value;
}
value = option.startsWith('_')
? getOptionFromNpmRc(fullOption)
: getOptionFromNpmCli(fullOption);
npmConfigOptionCache.set(fullOption, value);
return value;
}
开发者ID:baconwaffles，项目名称:angular-cli，代码行数:31，代码来源:npm.ts
示例3: getNpmConfigOption
function getNpmConfigOption(
option: string,
scope?: string,
tryWithoutScope?: boolean,
): Observable<string | undefined> {
if (scope && tryWithoutScope) {
return concat(
getNpmConfigOption(option, scope),
getNpmConfigOption(option),
).pipe(
filter(result => !!result),
defaultIfEmpty(),
first(),
);
}
const fullOption = `${scope ? scope + ':' : ''}${option}`;
let value = npmConfigOptionCache.get(fullOption);
if (value) {
return value;
}
const subject = new ReplaySubject<string | undefined>(1);
try {
exec(`npm get ${fullOption}`, (error, data) => {
if (error) {
subject.next();
} else {
data = data.trim();
if (!data || data === 'undefined' || data === 'null') {
subject.next();
} else {
subject.next(data);
}
}
subject.complete();
});
} catch {
subject.next();
subject.complete();
}
value = subject.asObservable();
npmConfigOptionCache.set(fullOption, value);
return value;
}
开发者ID:fmalcher，项目名称:angular-cli，代码行数:50，代码来源:npm.ts
示例4: callSource
export function callSource(source: Source, context: SchematicContext): Observable<Tree> {
const result = source(context);
if (isObservable(result)) {
// Only return the last Tree, and make sure it's a Tree.
return result.pipe(
defaultIfEmpty(),
last(),
tap(inner => {
if (!inner || !(TreeSymbol in inner)) {
throw new InvalidSourceResultException(inner);
}
}),
);
} else if (result && TreeSymbol in result) {
return observableOf(result);
} else {
return throwError(new InvalidSourceResultException(result));
}
}
开发者ID:angular，项目名称:angular-cli，代码行数:20，代码来源:call.ts
示例5: getNpmConfigOption
function getNpmConfigOption(
option: string,
scope?: string,
tryWithoutScope?: boolean,
): Observable<string | undefined> {
if (scope && tryWithoutScope) {
return concat(
getNpmConfigOption(option, scope),
getNpmConfigOption(option),
).pipe(
filter(result => !!result),
defaultIfEmpty(),
first(),
);
}
const fullOption = `${scope ? scope + ':' : ''}${option}`;
let value = npmConfigOptionCache.get(fullOption);
if (value) {
return value;
}
const subject = new ReplaySubject<string | undefined>(1);
const optionValue = npmConfig && npmConfig[fullOption];
if (optionValue == undefined || optionValue == null) {
subject.next();
} else {
subject.next(optionValue);
}
subject.complete();
value = subject.asObservable();
npmConfigOptionCache.set(fullOption, value);
return value;
}
开发者ID:rexebin，项目名称:angular-cli，代码行数:39，代码来源:npm.ts
示例6:
export function defaultIfEmpty<T, R>(this: Observable<T>, defaultValue: R = null): Observable<T | R> {
return higherOrder<T, R>(defaultValue)(this);
}
开发者ID:DallanQ，项目名称:rxjs，代码行数:3，代码来源:defaultIfEmpty.ts
示例7: of
observable1 = constructorZone1.run(() => {
return of().pipe(defaultIfEmpty('empty'));
});
开发者ID:angular，项目名称:zone.js，代码行数:3，代码来源:rxjs.Observable.default.spec.ts
示例8: it
it('should infer correctly with a defaultValue', () => {
const o = of(1, 2, 3).pipe(defaultIfEmpty(47)); // $ExpectType Observable<number>
});
开发者ID:jaychsu，项目名称:RxJS，代码行数:3，代码来源:defaultIfEmpty-spec.ts
注：本文中的rxjs/operators.defaultIfEmpty函数示例由纯净天空整理自Github/MSDocs等源码及文档管理平台，相关代码片段筛选自各路编程大神贡献的开源项目，源码版权归原作者所有，传播和使用请参考对应项目的License；未经允许，请勿转载。 |
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