import { EmptyError } from '../util/EmptyError'; import { filter } from './filter'; import { take } from './take'; import { defaultIfEmpty } from './defaultIfEmpty'; import { throwIfEmpty } from './throwIfEmpty'; import { identity } from '../util/identity'; export function first(predicate, defaultValue) { var hasDefaultValue = arguments.length >= 2; return function (source) { return source.pipe(predicate ? filter(function (v, i) { return predicate(v, i, source); }) : identity, take(1), hasDefaultValue ? defaultIfEmpty(defaultValue) : throwIfEmpty(function () { return new EmptyError(); })); }; } //# sourceMappingURL=first.js.map