@langchain/core
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Core LangChain.js abstractions and schemas
64 lines (63 loc) • 2.54 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.getPromptInputKey = exports.getOutputValue = exports.getInputValue = exports.BaseMemory = void 0;
/**
* 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.
*/
class BaseMemory {
}
exports.BaseMemory = 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.
*/
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;
};
exports.getInputValue = getInputValue;
/**
* 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.
*/
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;
};
exports.getOutputValue = getOutputValue;
/**
* 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.
*/
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];
}
exports.getPromptInputKey = getPromptInputKey;