@langchain/core/dist/memory.js

Core LangChain.js abstractions and schemas

/**
 * Abstract base class for memory in LangChain's Chains. Memory refers to
 * the state in Chains. It can be used to store information about past
 * executions of a Chain and inject that information into the inputs of
 * future executions of the Chain.
 */
export class BaseMemory {
}
const getValue = (values, key) => {
    if (key !== undefined) {
        return values[key];
    }
    const keys = Object.keys(values);
    if (keys.length === 1) {
        return values[keys[0]];
    }
};
/**
 * This function is used by memory classes to select the input value
 * to use for the memory. If there is only one input value, it is used.
 * If there are multiple input values, the inputKey must be specified.
 */
export const getInputValue = (inputValues, inputKey) => {
    const value = getValue(inputValues, inputKey);
    if (!value) {
        const keys = Object.keys(inputValues);
        throw new Error(`input values have ${keys.length} keys, you must specify an input key or pass only 1 key as input`);
    }
    return value;
};
/**
 * This function is used by memory classes to select the output value
 * to use for the memory. If there is only one output value, it is used.
 * If there are multiple output values, the outputKey must be specified.
 * If no outputKey is specified, an error is thrown.
 */
export const getOutputValue = (outputValues, outputKey) => {
    const value = getValue(outputValues, outputKey);
    if (!value && value !== "") {
        const keys = Object.keys(outputValues);
        throw new Error(`output values have ${keys.length} keys, you must specify an output key or pass only 1 key as output`);
    }
    return value;
};
/**
 * Function used by memory classes to get the key of the prompt input,
 * excluding any keys that are memory variables or the "stop" key. If
 * there is not exactly one prompt input key, an error is thrown.
 */
export function getPromptInputKey(inputs, memoryVariables) {
    const promptInputKeys = Object.keys(inputs).filter((key) => !memoryVariables.includes(key) && key !== "stop");
    if (promptInputKeys.length !== 1) {
        throw new Error(`One input key expected, but got ${promptInputKeys.length}`);
    }
    return promptInputKeys[0];
}