60 lines
2 KiB
JavaScript
60 lines
2 KiB
JavaScript
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import { BaseOutputParser, OutputParserException, } from "@langchain/core/output_parsers";
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/**
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* Class to parse the output of an LLM call to a date.
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* @augments BaseOutputParser
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*/
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export class DatetimeOutputParser extends BaseOutputParser {
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constructor() {
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super(...arguments);
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Object.defineProperty(this, "lc_namespace", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: ["langchain", "output_parsers"]
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});
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Object.defineProperty(this, "lc_serializable", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: true
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});
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/**
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* ISO 8601 date time standard.
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*/
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Object.defineProperty(this, "format", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: "YYYY-MM-DDTHH:mm:ssZ"
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});
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}
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static lc_name() {
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return "DatetimeOutputParser";
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}
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/**
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* Parses the given text into a Date.
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* If the parsing fails, throws an OutputParserException.
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* @param text The text to parse.
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* @returns A date object.
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*/
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async parse(text) {
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const parsedDate = new Date(text.trim());
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if (Number.isNaN(parsedDate.getTime())) {
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throw new OutputParserException(`Could not parse output: ${text}`, text);
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}
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return parsedDate;
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}
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/**
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* Provides instructions on the expected format of the response for the
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* CommaSeparatedListOutputParser.
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* @returns A string containing instructions on the expected format of the response.
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*/
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getFormatInstructions() {
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return [
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`Your response should be a datetime string that matches the following pattern: "${this.format}".`,
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`Examples: 2011-10-05T14:48:00Z, 2019-01-01T00:00:00Z, 1932-04-21T04:42:23Z`,
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`Return ONLY this string, no other words!`,
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].join("\n\n");
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}
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}
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