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List parser

This output parser can be used when you want to return a list of comma-separated items.

npm install @langchain/openai
import { OpenAI } from "@langchain/openai";
import { PromptTemplate } from "@langchain/core/prompts";
import { CommaSeparatedListOutputParser } from "@langchain/core/output_parsers";
import { RunnableSequence } from "@langchain/core/runnables";

export const run = async () => {
// With a `CommaSeparatedListOutputParser`, we can parse a comma separated list.
const parser = new CommaSeparatedListOutputParser();

const chain = RunnableSequence.from([
PromptTemplate.fromTemplate("List five {subject}.\n{format_instructions}"),
new OpenAI({ temperature: 0 }),

List five ice cream flavors.
Your response should be a list of comma separated values, eg: `foo, bar, baz`
const response = await chain.invoke({
subject: "ice cream flavors",
format_instructions: parser.getFormatInstructions(),

'Mint Chocolate Chip',
'Cookies and Cream'

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