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*   [Get started](/v0.1/docs/get_started/)
    
    *   [Introduction](/v0.1/docs/get_started/introduction/)
    *   [Installation](/v0.1/docs/get_started/installation/)
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*   [LangChain Expression Language](/v0.1/docs/expression_language/)
    
    *   [Get started](/v0.1/docs/expression_language/get_started/)
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*   [Modules](/v0.1/docs/modules/)
    
    *   [Model I/O](/v0.1/docs/modules/model_io/)
        
        *   [Quickstart](/v0.1/docs/modules/model_io/quick_start/)
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            *   [Quick Start](/v0.1/docs/modules/model_io/output_parsers/quick_start/)
            *   [Custom output parsers](/v0.1/docs/modules/model_io/output_parsers/custom/)
            *   [Output Parser Types](/v0.1/docs/modules/model_io/output_parsers/types/)
                
                *   [String output parser](/v0.1/docs/modules/model_io/output_parsers/types/string/)
                *   [HTTP Response Output Parser](/v0.1/docs/modules/model_io/output_parsers/types/http_response/)
                *   [JSON Output Functions Parser](/v0.1/docs/modules/model_io/output_parsers/types/json_functions/)
                *   [Bytes output parser](/v0.1/docs/modules/model_io/output_parsers/types/bytes/)
                *   [Combining output parsers](/v0.1/docs/modules/model_io/output_parsers/types/combining_output_parser/)
                *   [List parser](/v0.1/docs/modules/model_io/output_parsers/types/csv/)
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                *   [Structured output parser](/v0.1/docs/modules/model_io/output_parsers/types/structured/)
                *   [XML output parser](/v0.1/docs/modules/model_io/output_parsers/types/xml/)
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*   [](/v0.1/)
*   [Modules](/v0.1/docs/modules/)
*   [Model I/O](/v0.1/docs/modules/model_io/)
*   [Output Parsers](/v0.1/docs/modules/model_io/output_parsers/)
*   [Output Parser Types](/v0.1/docs/modules/model_io/output_parsers/types/)
*   Combining output parsers

Combining output parsers
========================

Output parsers can be combined using `CombiningOutputParser`. This output parser takes in a list of output parsers, and will ask for (and parse) a combined output that contains all the fields of all the parsers.

tip

See [this section for general instructions on installing integration packages](/v0.1/docs/get_started/installation/#installing-integration-packages).

*   npm
*   Yarn
*   pnpm

    npm install @langchain/openai

    yarn add @langchain/openai

    pnpm add @langchain/openai

    import { OpenAI } from "@langchain/openai";import {  StructuredOutputParser,  RegexParser,  CombiningOutputParser,} from "langchain/output_parsers";import { PromptTemplate } from "@langchain/core/prompts";import { RunnableSequence } from "@langchain/core/runnables";const answerParser = StructuredOutputParser.fromNamesAndDescriptions({  answer: "answer to the user's question",  source: "source used to answer the user's question, should be a website.",});const confidenceParser = new RegexParser(  /Confidence: (A|B|C), Explanation: (.*)/,  ["confidence", "explanation"],  "noConfidence");const parser = new CombiningOutputParser(answerParser, confidenceParser);const chain = RunnableSequence.from([  PromptTemplate.fromTemplate(    "Answer the users question as best as possible.\n{format_instructions}\n{question}"  ),  new OpenAI({ temperature: 0 }),  parser,]);/*Answer the users question as best as possible.Return the following outputs, each formatted as described below:Output 1:The output should be formatted as a JSON instance that conforms to the JSON schema below.As an example, for the schema {{"properties": {{"foo": {{"title": "Foo", "description": "a list of strings", "type": "array", "items": {{"type": "string"}}}}}}, "required": ["foo"]}}}}the object {{"foo": ["bar", "baz"]}} is a well-formatted instance of the schema. The object {{"properties": {{"foo": ["bar", "baz"]}}}} is not well-formatted.Here is the output schema:```{"type":"object","properties":{"answer":{"type":"string","description":"answer to the user's question"},"source":{"type":"string","description":"source used to answer the user's question, should be a website."}},"required":["answer","source"],"additionalProperties":false,"$schema":"http://json-schema.org/draft-07/schema#"}```Output 2:Your response should match the following regex: /Confidence: (A|B|C), Explanation: (.*)/What is the capital of France?*/const response = await chain.invoke({  question: "What is the capital of France?",  format_instructions: parser.getFormatInstructions(),});console.log(response);/*{  answer: 'Paris',  source: 'https://www.worldatlas.com/articles/what-is-the-capital-of-france.html',  confidence: 'A',  explanation: 'The capital of France is Paris.'}*/

#### API Reference:

*   [OpenAI](https://api.js.langchain.com/classes/langchain_openai.OpenAI.html) from `@langchain/openai`
*   [StructuredOutputParser](https://api.js.langchain.com/classes/langchain_output_parsers.StructuredOutputParser.html) from `langchain/output_parsers`
*   [RegexParser](https://api.js.langchain.com/classes/langchain_output_parsers.RegexParser.html) from `langchain/output_parsers`
*   [CombiningOutputParser](https://api.js.langchain.com/classes/langchain_output_parsers.CombiningOutputParser.html) from `langchain/output_parsers`
*   [PromptTemplate](https://api.js.langchain.com/classes/langchain_core_prompts.PromptTemplate.html) from `@langchain/core/prompts`
*   [RunnableSequence](https://api.js.langchain.com/classes/langchain_core_runnables.RunnableSequence.html) from `@langchain/core/runnables`

* * *

#### Help us out by providing feedback on this documentation page:

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