chrono-node
Version:
A natural language date parser in Javascript
59 lines (49 loc) • 2.19 kB
text/typescript
import { MergingRefiner } from "../../../common/abstractRefiners";
import { ParsingComponents, ParsingResult, ReferenceWithTimezone } from "../../../results";
import { parseTimeUnits } from "../constants";
import { reverseTimeUnits } from "../../../utils/timeunits";
function hasImpliedEarlierReferenceDate(result: ParsingResult): boolean {
return result.text.match(/\s+(prima|dal)$/i) != null;
}
function hasImpliedLaterReferenceDate(result: ParsingResult): boolean {
return result.text.match(/\s+(dopo|dal|fino)$/i) != null;
}
/**
* Merges an absolute date with a relative date.
* - 2 weeks before 2020-02-13
* - 2 days after next Friday
*/
export default class ENMergeRelativeDateRefiner extends MergingRefiner {
patternBetween(): RegExp {
return /^\s*$/i;
}
shouldMergeResults(textBetween: string, currentResult: ParsingResult, nextResult: ParsingResult): boolean {
// Dates need to be next to each other to get merged
if (!textBetween.match(this.patternBetween())) {
return false;
}
// Check if any relative tokens were swallowed by the first date.
// E.g. [<relative_date1> from] [<date2>]
if (!hasImpliedEarlierReferenceDate(currentResult) && !hasImpliedLaterReferenceDate(currentResult)) {
return false;
}
// make sure that <date2> implies an absolute date
return !!nextResult.start.get("day") && !!nextResult.start.get("month") && !!nextResult.start.get("year");
}
mergeResults(textBetween: string, currentResult: ParsingResult, nextResult: ParsingResult): ParsingResult {
let timeUnits = parseTimeUnits(currentResult.text);
if (hasImpliedEarlierReferenceDate(currentResult)) {
timeUnits = reverseTimeUnits(timeUnits);
}
const components = ParsingComponents.createRelativeFromReference(
new ReferenceWithTimezone(nextResult.start.date()),
timeUnits
);
return new ParsingResult(
nextResult.reference,
currentResult.index,
`${currentResult.text}${textBetween}${nextResult.text}`,
components
);
}
}