89 lines
3.2 KiB
JavaScript
89 lines
3.2 KiB
JavaScript
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import { BaseOutputParser } from "@langchain/core/output_parsers";
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/**
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* Class to combine multiple output parsers
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* @augments BaseOutputParser
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*/
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export class CombiningOutputParser extends BaseOutputParser {
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static lc_name() {
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return "CombiningOutputParser";
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}
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constructor(fields, ...parsers) {
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if (parsers.length > 0 || !("parsers" in fields)) {
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// eslint-disable-next-line no-param-reassign
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fields = {
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parsers: [fields, ...parsers],
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};
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}
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super(fields);
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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", "combining"]
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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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Object.defineProperty(this, "parsers", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "outputDelimiter", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: "-----"
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});
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this.parsers = fields.parsers;
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}
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/**
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* Method to parse an input string using the parsers in the parsers array.
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* The parsed outputs are combined into a single object and returned.
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* @param input The input string to parse.
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* @param callbacks Optional Callbacks object.
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* @returns A Promise that resolves to a CombinedOutput object.
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*/
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async parse(input, callbacks) {
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const inputs = input
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.trim()
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.split(new RegExp(`${this.outputDelimiter}Output \\d+${this.outputDelimiter}`))
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.slice(1);
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const ret = {};
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for (const [i, p] of this.parsers.entries()) {
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let parsed;
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try {
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let extracted = inputs[i].includes("```")
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? inputs[i].trim().split(/```/)[1]
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: inputs[i].trim();
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if (extracted.endsWith(this.outputDelimiter)) {
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extracted = extracted.slice(0, -this.outputDelimiter.length);
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}
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parsed = await p.parse(extracted, callbacks);
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}
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catch (e) {
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parsed = await p.parse(input.trim(), callbacks);
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}
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Object.assign(ret, parsed);
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}
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return ret;
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}
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/**
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* Method to get instructions on how to format the LLM output. The
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* instructions are based on the parsers array and the outputDelimiter.
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* @returns A string with format instructions.
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*/
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getFormatInstructions() {
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return `${[
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`Return the following ${this.parsers.length} outputs, each formatted as described below. Include the delimiter characters "${this.outputDelimiter}" in your response:`,
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...this.parsers.map((p, i) => `${this.outputDelimiter}Output ${i + 1}${this.outputDelimiter}\n${p
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.getFormatInstructions()
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.trim()}\n${this.outputDelimiter}`),
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].join("\n\n")}\n`;
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}
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}
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