Class SimpleSequentialChain

Simple chain where a single string output of one chain is fed directly into the next.

Example

import { SimpleSequentialChain, LLMChain } from "langchain/chains";
import { OpenAI } from "langchain/llms/openai";
import { PromptTemplate } from "langchain/prompts";

// This is an LLMChain to write a synopsis given a title of a play.
const llm = new OpenAI({ temperature: 0 });
const template = `You are a playwright. Given the title of play, it is your job to write a synopsis for that title.

Title: {title}
Playwright: This is a synopsis for the above play:`
const promptTemplate = new PromptTemplate({ template, inputVariables: ["title"] });
const synopsisChain = new LLMChain({ llm, prompt: promptTemplate });


// This is an LLMChain to write a review of a play given a synopsis.
const reviewLLM = new OpenAI({ temperature: 0 })
const reviewTemplate = `You are a play critic from the New York Times. Given the synopsis of play, it is your job to write a review for that play.

Play Synopsis:
{synopsis}
Review from a New York Times play critic of the above play:`
const reviewPromptTemplate = new PromptTemplate({ template: reviewTemplate, inputVariables: ["synopsis"] });
const reviewChain = new LLMChain({ llm: reviewLLM, prompt: reviewPromptTemplate });

const overallChain = new SimpleSequentialChain({chains: [synopsisChain, reviewChain], verbose:true})
const review = await overallChain.run("Tragedy at sunset on the beach")
// the variable review contains resulting play review.

Hierarchy

BaseChain
- SimpleSequentialChain

Implements

SimpleSequentialChainInput

Constructors

constructor

new SimpleSequentialChain(fields): SimpleSequentialChain
Parameters
- fields: SimpleSequentialChainInput
Returns SimpleSequentialChain
Overrides BaseChain.constructor
- Defined in langchain/src/chains/sequential_chain.ts:265

Properties

chains

chains: BaseChain<ChainValues, ChainValues>[]

Array of chains to run as a sequence. The chains are run in order they appear in the array.

inputKey

inputKey: string = "input"

lc_kwargs

lc_kwargs: SerializedFields

lc_serializable

lc_serializable: boolean = false

outputKey

outputKey: string = "output"

trimOutputs

trimOutputs: boolean

Whether or not to trim the intermediate outputs.

verbose

verbose: boolean

Whether to print out response text.

`Optional` callbacks

callbacks?: Callbacks

`Optional` memory

memory?: BaseMemory

`Optional` metadata

metadata?: Record<string, unknown>

`Optional` tags

tags?: string[]

`Protected` lc_runnable

lc_runnable: boolean = true

Accessors

inputKeys

get inputKeys(): string[]
Returns string[]
Overrides BaseChain.inputKeys
- Defined in langchain/src/chains/sequential_chain.ts:257

lc_aliases

get lc_aliases(): undefined | {
[key: string]: string;
}
A map of aliases for constructor args. Keys are the attribute names, e.g. "foo". Values are the alias that will replace the key in serialization. This is used to eg. make argument names match Python.

Returns undefined | {
[key: string]: string;
}
Inherited from BaseChain.lc_aliases
- Defined in langchain/src/load/serializable.ts:132

lc_attributes

get lc_attributes(): undefined | {
[key: string]: undefined;
}
A map of additional attributes to merge with constructor args. Keys are the attribute names, e.g. "foo". Values are the attribute values, which will be serialized. These attributes need to be accepted by the constructor as arguments.

Returns undefined | {
[key: string]: undefined;
}
Inherited from BaseChain.lc_attributes
- Defined in langchain/src/base_language/index.ts:64

lc_id

get lc_id(): string[]
The final serialized identifier for the module.

Returns string[]
Inherited from BaseChain.lc_id
- Defined in langchain/src/load/serializable.ts:100

lc_namespace

get lc_namespace(): string[]
A path to the module that contains the class, eg. ["langchain", "llms"] Usually should be the same as the entrypoint the class is exported from.

Returns string[]
Inherited from BaseChain.lc_namespace
- Defined in langchain/src/chains/base.ts:37

lc_secrets

get lc_secrets(): undefined | {
[key: string]: string;
}
A map of secrets, which will be omitted from serialization. Keys are paths to the secret in constructor args, e.g. "foo.bar.baz". Values are the secret ids, which will be used when deserializing.

Returns undefined | {
[key: string]: string;
}
Inherited from BaseChain.lc_secrets
- Defined in langchain/src/load/serializable.ts:112

outputKeys

get outputKeys(): string[]
Returns string[]
Overrides BaseChain.outputKeys
- Defined in langchain/src/chains/sequential_chain.ts:261

Methods

_batchWithConfig

_batchWithConfig<T>(func, inputs, options?, batchOptions?): Promise<(Error | ChainValues)[]>
Internal method that handles batching and configuration for a runnable It takes a function, input values, and optional configuration, and returns a promise that resolves to the output values.
Type Parameters
- T extends ChainValues
Parameters
- func: ((inputs, options?, runManagers?, batchOptions?) => Promise<(Error | ChainValues)[]>)
  
  The function to be executed for each input value.
  - - (inputs, options?, runManagers?, batchOptions?): Promise<(Error | ChainValues)[]>
    - Parameters
      
      inputs: T[]
      
      Optional options: Partial<BaseCallbackConfig>[]
      
      Optional runManagers: (undefined | CallbackManagerForChainRun)[]
      
      Optional batchOptions: RunnableBatchOptions
      
      Returns Promise<(Error | ChainValues)[]>
- inputs: T[]
- Optional options: Partial<BaseCallbackConfig & {
  runType?: string;
  }> | Partial<BaseCallbackConfig & {
  runType?: string;
  }>[]
- Optional batchOptions: RunnableBatchOptions
Returns Promise<(Error | ChainValues)[]>
A promise that resolves to the output values.
Inherited from BaseChain._batchWithConfig
- Defined in langchain/src/schema/runnable/base.ts:289

_chainType

_chainType(): "simple_sequential_chain"
Return the string type key uniquely identifying this class of chain.

Returns "simple_sequential_chain"
Overrides BaseChain._chainType
- Defined in langchain/src/chains/sequential_chain.ts:319

_patchConfig

_patchConfig(config?, callbackManager?): Partial<BaseCallbackConfig>
Parameters
- config: Partial<BaseCallbackConfig> = {}
- callbackManager: undefined | CallbackManager = undefined
Returns Partial<BaseCallbackConfig>
Inherited from BaseChain._patchConfig
- Defined in langchain/src/schema/runnable/base.ts:431

_streamIterator

_streamIterator(input, options?): AsyncGenerator<ChainValues, any, unknown>
Default streaming implementation. Subclasses should override this method if they support streaming output.
Parameters
- input: ChainValues
- Optional options: Partial<BaseCallbackConfig>
Returns AsyncGenerator<ChainValues, any, unknown>
Inherited from BaseChain._streamIterator
- Defined in langchain/src/schema/runnable/base.ts:209

apply

apply(inputs, config?): Promise<ChainValues[]>
Call the chain on all inputs in the list
Parameters
- inputs: ChainValues[]
- Optional config: (Callbacks | BaseCallbackConfig)[]
Returns Promise<ChainValues[]>
Inherited from BaseChain.apply
- Defined in langchain/src/chains/base.ts:221

batch

batch(inputs, options?, batchOptions?): Promise<ChainValues[]>
Default implementation of batch, which calls invoke N times. Subclasses should override this method if they can batch more efficiently.
Parameters
- inputs: ChainValues[]
  
  Array of inputs to each batch call.
- Optional options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]
  
  Either a single call options object to apply to each batch call or an array for each call.
- Optional batchOptions: RunnableBatchOptions & {
  returnExceptions?: false;
  }
Returns Promise<ChainValues[]>
An array of RunOutputs, or mixed RunOutputs and errors if batchOptions.returnExceptions is set
Inherited from BaseChain.batch
- Defined in langchain/src/schema/runnable/base.ts:157
batch(inputs, options?, batchOptions?): Promise<(Error | ChainValues)[]>
Parameters
- inputs: ChainValues[]
- Optional options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]
- Optional batchOptions: RunnableBatchOptions & {
  returnExceptions: true;
  }
Returns Promise<(Error | ChainValues)[]>
Inherited from BaseChain.batch
- Defined in langchain/src/schema/runnable/base.ts:163
batch(inputs, options?, batchOptions?): Promise<(Error | ChainValues)[]>
Parameters
- inputs: ChainValues[]
- Optional options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]
- Optional batchOptions: RunnableBatchOptions
Returns Promise<(Error | ChainValues)[]>
Inherited from BaseChain.batch
- Defined in langchain/src/schema/runnable/base.ts:169

bind

bind(kwargs): Runnable<ChainValues, ChainValues, BaseCallbackConfig>
Bind arguments to a Runnable, returning a new Runnable.
Parameters
- kwargs: Partial<BaseCallbackConfig>
Returns Runnable<ChainValues, ChainValues, BaseCallbackConfig>
A new RunnableBinding that, when invoked, will apply the bound args.
Inherited from BaseChain.bind
- Defined in langchain/src/schema/runnable/base.ts:66

call

call(values, config?, tags?): Promise<ChainValues>
Run the core logic of this chain and add to output if desired.

Wraps _call and handles memory.
Parameters
- values: ChainValues & {
  signal?: AbortSignal;
  timeout?: number;
  }
- Optional config: Callbacks | BaseCallbackConfig
- Optional tags: string[]
  
  Deprecated
Returns Promise<ChainValues>
Inherited from BaseChain.call
- Defined in langchain/src/chains/base.ts:161

invoke

invoke(input, config?): Promise<ChainValues>
Invoke the chain with the provided input and returns the output.
Parameters
- input: ChainValues
  
  Input values for the chain run.
- Optional config: BaseCallbackConfig
  
  Optional configuration for the Runnable.
Returns Promise<ChainValues>
Promise that resolves with the output of the chain run.
Inherited from BaseChain.invoke
- Defined in langchain/src/chains/base.ts:82

map

map(): Runnable<ChainValues[], ChainValues[], BaseCallbackConfig>
Return a new Runnable that maps a list of inputs to a list of outputs, by calling invoke() with each input.

Returns Runnable<ChainValues[], ChainValues[], BaseCallbackConfig>
Inherited from BaseChain.map
- Defined in langchain/src/schema/runnable/base.ts:77

pipe

pipe<NewRunOutput>(coerceable): RunnableSequence<ChainValues, Exclude<NewRunOutput, Error>>
Create a new runnable sequence that runs each individual runnable in series, piping the output of one runnable into another runnable or runnable-like.
Type Parameters
- NewRunOutput
Parameters
- coerceable: RunnableLike<ChainValues, NewRunOutput>
  
  A runnable, function, or object whose values are functions or runnables.
Returns RunnableSequence<ChainValues, Exclude<NewRunOutput, Error>>
A new runnable sequence.
Inherited from BaseChain.pipe
- Defined in langchain/src/schema/runnable/base.ts:453

run

run(input, config?): Promise<string>
Parameters
- input: any
- Optional config: Callbacks | BaseCallbackConfig
Returns Promise<string>
Inherited from BaseChain.run
- Defined in langchain/src/chains/base.ts:110

serialize

serialize(): SerializedSimpleSequentialChain
Return a json-like object representing this chain.

Returns SerializedSimpleSequentialChain
Overrides BaseChain.serialize
- Defined in langchain/src/chains/sequential_chain.ts:333

stream

stream(input, options?): Promise<IterableReadableStream<ChainValues>>
Stream output in chunks.
Parameters
- input: ChainValues
- Optional options: Partial<BaseCallbackConfig>
Returns Promise<IterableReadableStream<ChainValues>>
A readable stream that is also an iterable.
Inherited from BaseChain.stream
- Defined in langchain/src/schema/runnable/base.ts:222

streamLog

streamLog(input, options?, streamOptions?): AsyncGenerator<RunLogPatch, any, unknown>
Stream all output from a runnable, as reported to the callback system. This includes all inner runs of LLMs, Retrievers, Tools, etc. Output is streamed as Log objects, which include a list of jsonpatch ops that describe how the state of the run has changed in each step, and the final state of the run. The jsonpatch ops can be applied in order to construct state.
Parameters
- input: ChainValues
- Optional options: Partial<BaseCallbackConfig>
- Optional streamOptions: Omit<LogStreamCallbackHandlerInput, "autoClose">
Returns AsyncGenerator<RunLogPatch, any, unknown>
Inherited from BaseChain.streamLog
- Defined in langchain/src/schema/runnable/base.ts:499

toJSON

toJSON(): Serialized
Returns Serialized
Inherited from BaseChain.toJSON
- Defined in langchain/src/load/serializable.ts:140

toJSONNotImplemented

toJSONNotImplemented(): SerializedNotImplemented
Returns SerializedNotImplemented
Inherited from BaseChain.toJSONNotImplemented
- Defined in langchain/src/load/serializable.ts:214

transform

transform(generator, options): AsyncGenerator<ChainValues, any, unknown>
Default implementation of transform, which buffers input and then calls stream. Subclasses should override this method if they can start producing output while input is still being generated.
Parameters
- generator: AsyncGenerator<ChainValues, any, unknown>
- options: Partial<BaseCallbackConfig>
Returns AsyncGenerator<ChainValues, any, unknown>
Inherited from BaseChain.transform
- Defined in langchain/src/schema/runnable/base.ts:470

withConfig

withConfig(config): RunnableBinding<ChainValues, ChainValues, BaseCallbackConfig>
Bind config to a Runnable, returning a new Runnable.
Parameters
- config: BaseCallbackConfig
  
  New configuration parameters to attach to the new runnable.
Returns RunnableBinding<ChainValues, ChainValues, BaseCallbackConfig>
A new RunnableBinding with a config matching what's passed.
Inherited from BaseChain.withConfig
- Defined in langchain/src/schema/runnable/base.ts:106

withFallbacks

withFallbacks(fields): RunnableWithFallbacks<ChainValues, ChainValues>
Create a new runnable from the current one that will try invoking other passed fallback runnables if the initial invocation fails.
Parameters
- fields: {
  fallbacks: Runnable<ChainValues, ChainValues, BaseCallbackConfig>[];
  }
  - fallbacks: Runnable<ChainValues, ChainValues, BaseCallbackConfig>[]
    
    Other runnables to call if the runnable errors.
Returns RunnableWithFallbacks<ChainValues, ChainValues>
A new RunnableWithFallbacks.
Inherited from BaseChain.withFallbacks
- Defined in langchain/src/schema/runnable/base.ts:123

withRetry

withRetry(fields?): RunnableRetry<ChainValues, ChainValues, BaseCallbackConfig>
Add retry logic to an existing runnable.
Parameters
- Optional fields: {
  onFailedAttempt?: RunnableRetryFailedAttemptHandler;
  stopAfterAttempt?: number;
  }
  - Optional onFailedAttempt?: RunnableRetryFailedAttemptHandler
  - Optional stopAfterAttempt?: number
Returns RunnableRetry<ChainValues, ChainValues, BaseCallbackConfig>
A new RunnableRetry that, when invoked, will retry according to the parameters.
Inherited from BaseChain.withRetry
- Defined in langchain/src/schema/runnable/base.ts:87

`Static` deserialize

deserialize(data): Promise<SimpleSequentialChain>
Load a chain from a json-like object describing it.
Parameters
- data: SerializedSimpleSequentialChain
Returns Promise<SimpleSequentialChain>
Overrides BaseChain.deserialize
- Defined in langchain/src/chains/sequential_chain.ts:323

`Static` isRunnable

isRunnable(thing): thing is Runnable<any, any, BaseCallbackConfig>
Parameters
- thing: any
Returns thing is Runnable<any, any, BaseCallbackConfig>
Inherited from BaseChain.isRunnable
- Defined in langchain/src/schema/runnable/base.ts:549

`Static` lc_name

lc_name(): string
The name of the serializable. Override to provide an alias or to preserve the serialized module name in minified environments.

Implemented as a static method to support loading logic.

Returns string
Overrides BaseChain.lc_name
- Defined in langchain/src/chains/sequential_chain.ts:245

`Protected` _callWithConfig

_callWithConfig<T>(func, input, options?): Promise<ChainValues>
Type Parameters
- T extends ChainValues
Parameters
- func: ((input) => Promise<ChainValues>) | ((input, config?, runManager?) => Promise<ChainValues>)
- input: T
- Optional options: Partial<BaseCallbackConfig> & {
  runType?: string;
  }
Returns Promise<ChainValues>
Inherited from BaseChain._callWithConfig
- Defined in langchain/src/schema/runnable/base.ts:248

`Protected` _formatValues

_formatValues(values): Promise<ChainValues & {
signal?: AbortSignal;
timeout?: number;
}>
Parameters
- values: ChainValues & {
  signal?: AbortSignal;
  timeout?: number;
  }
Returns Promise<ChainValues & {
signal?: AbortSignal;
timeout?: number;
}>
Inherited from BaseChain._formatValues
- Defined in langchain/src/chains/base.ts:137

`Protected` _getOptionsList

_getOptionsList(options, length?): Partial<BaseCallbackConfig & {
runType?: string;
}>[]
Parameters
- options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]
- length: number = 0
Returns Partial<BaseCallbackConfig & {
runType?: string;
}>[]
Inherited from BaseChain._getOptionsList
- Defined in langchain/src/schema/runnable/base.ts:133

`Protected` _separateRunnableConfigFromCallOptions

_separateRunnableConfigFromCallOptions(options?): [BaseCallbackConfig, Omit<Partial<BaseCallbackConfig>, keyof BaseCallbackConfig>]
Parameters
- options: Partial<BaseCallbackConfig> = {}
Returns [BaseCallbackConfig, Omit<Partial<BaseCallbackConfig>, keyof BaseCallbackConfig>]
Inherited from BaseChain._separateRunnableConfigFromCallOptions
- Defined in langchain/src/schema/runnable/base.ts:231

`Protected` _transformStreamWithConfig

_transformStreamWithConfig<I, O>(inputGenerator, transformer, options?): AsyncGenerator<O, any, unknown>
Helper method to transform an Iterator of Input values into an Iterator of Output values, with callbacks. Use this to implement stream() or transform() in Runnable subclasses.
Type Parameters
- I extends ChainValues
- O extends ChainValues
Parameters
- inputGenerator: AsyncGenerator<I, any, unknown>
- transformer: ((generator, runManager?, options?) => AsyncGenerator<O, any, unknown>)
  - - (generator, runManager?, options?): AsyncGenerator<O, any, unknown>
    - Parameters
      
      generator: AsyncGenerator<I, any, unknown>
      
      Optional runManager: CallbackManagerForChainRun
      
      Optional options: Partial<BaseCallbackConfig>
      
      Returns AsyncGenerator<O, any, unknown>
- Optional options: BaseCallbackConfig & {
  runType?: string;
  }
Returns AsyncGenerator<O, any, unknown>
Inherited from BaseChain._transformStreamWithConfig
- Defined in langchain/src/schema/runnable/base.ts:341

Class SimpleSequentialChain

Example

Hierarchy

Implements

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Parameters

fields: SimpleSequentialChainInput

Returns SimpleSequentialChain

Properties

chains

inputKey

lc_kwargs

lc_serializable

outputKey

trimOutputs

verbose

Optional callbacks

Optional memory

Optional metadata

Optional tags

Protected lc_runnable

Accessors

inputKeys

Returns string[]

lc_aliases

Returns undefined | { [key: string]: string; }

lc_attributes

Returns undefined | { [key: string]: undefined; }

lc_id

Returns string[]

lc_namespace

Returns string[]

lc_secrets

Returns undefined | { [key: string]: string; }

outputKeys

Returns string[]

Methods

_batchWithConfig

Type Parameters

T extends ChainValues

Parameters

func: ((inputs, options?, runManagers?, batchOptions?) => Promise<(Error | ChainValues)[]>)

Parameters

inputs: T[]

Optional options: Partial<BaseCallbackConfig>[]

Optional runManagers: (undefined | CallbackManagerForChainRun)[]

Optional batchOptions: RunnableBatchOptions

Returns Promise<(Error | ChainValues)[]>

inputs: T[]

Optional options: Partial<BaseCallbackConfig & { runType?: string; }> | Partial<BaseCallbackConfig & { runType?: string; }>[]

Optional batchOptions: RunnableBatchOptions

Returns Promise<(Error | ChainValues)[]>

_chainType

Returns "simple_sequential_chain"

_patchConfig

Parameters

config: Partial<BaseCallbackConfig> = {}

callbackManager: undefined | CallbackManager = undefined

Returns Partial<BaseCallbackConfig>

_streamIterator

Parameters

input: ChainValues

Optional options: Partial<BaseCallbackConfig>

Returns AsyncGenerator<ChainValues, any, unknown>

apply

Parameters

inputs: ChainValues[]

Optional config: (Callbacks | BaseCallbackConfig)[]

Returns Promise<ChainValues[]>

batch

Parameters

inputs: ChainValues[]

Optional options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]

Optional batchOptions: RunnableBatchOptions & { returnExceptions?: false; }

`Optional` callbacks

`Optional` memory

`Optional` metadata

`Optional` tags

`Protected` lc_runnable

Returns undefined | {
[key: string]: string;
}

Returns undefined | {
[key: string]: undefined;
}

Returns undefined | {
[key: string]: string;
}

`Optional` options: Partial<BaseCallbackConfig>[]

`Optional` runManagers: (undefined | CallbackManagerForChainRun)[]

`Optional` batchOptions: RunnableBatchOptions

`Optional` options: Partial<BaseCallbackConfig & {
runType?: string;
}> | Partial<BaseCallbackConfig & {
runType?: string;
}>[]

`Optional` batchOptions: RunnableBatchOptions

`Optional` options: Partial<BaseCallbackConfig>

`Optional` config: (Callbacks | BaseCallbackConfig)[]

`Optional` options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]

`Optional` batchOptions: RunnableBatchOptions & {
returnExceptions?: false;
}

`Optional` options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]

`Optional` batchOptions: RunnableBatchOptions & {
returnExceptions: true;
}

`Optional` options: Partial<BaseCallbackConfig> | Partial<BaseCallbackConfig>[]

`Optional` batchOptions: RunnableBatchOptions

values: ChainValues & {
signal?: AbortSignal;
timeout?: number;
}

`Optional` config: Callbacks | BaseCallbackConfig

`Optional` tags: string[]

`Optional` config: BaseCallbackConfig

`Optional` config: Callbacks | BaseCallbackConfig

`Optional` options: Partial<BaseCallbackConfig>

`Optional` options: Partial<BaseCallbackConfig>

`Optional` streamOptions: Omit<LogStreamCallbackHandlerInput, "autoClose">

fields: {
fallbacks: Runnable<ChainValues, ChainValues, BaseCallbackConfig>[];
}