@langchain/core/dist/load/index.js

Core LangChain.js abstractions and schemas

import { keyFromJson, mapKeys } from "./map_keys.js";
import { get_lc_unique_name } from "./serializable.js";
import { getEnvironmentVariable } from "../utils/env.js";
import { optionalImportEntrypoints } from "./import_constants.js";
import { import_map_exports } from "./import_map.js";

//#region src/load/index.ts
function combineAliasesAndInvert(constructor) {
	const aliases = {};
	for (let current = constructor; current && current.prototype; current = Object.getPrototypeOf(current)) Object.assign(aliases, Reflect.get(current.prototype, "lc_aliases"));
	return Object.entries(aliases).reduce((acc, [key, value]) => {
		acc[value] = key;
		return acc;
	}, {});
}
async function reviver(value) {
	const { optionalImportsMap = {}, optionalImportEntrypoints: optionalImportEntrypoints$1 = [], importMap = {}, secretsMap = {}, path = ["$"] } = this;
	const pathStr = path.join(".");
	if (typeof value === "object" && value !== null && !Array.isArray(value) && "lc" in value && "type" in value && "id" in value && value.lc === 1 && value.type === "secret") {
		const serialized = value;
		const [key] = serialized.id;
		if (key in secretsMap) return secretsMap[key];
		else {
			const secretValueInEnv = getEnvironmentVariable(key);
			if (secretValueInEnv) return secretValueInEnv;
			else throw new Error(`Missing key "${key}" for ${pathStr} in load(secretsMap={})`);
		}
	} else if (typeof value === "object" && value !== null && !Array.isArray(value) && "lc" in value && "type" in value && "id" in value && value.lc === 1 && value.type === "not_implemented") {
		const serialized = value;
		const str = JSON.stringify(serialized);
		throw new Error(`Trying to load an object that doesn't implement serialization: ${pathStr} -> ${str}`);
	} else if (typeof value === "object" && value !== null && !Array.isArray(value) && "lc" in value && "type" in value && "id" in value && "kwargs" in value && value.lc === 1) {
		const serialized = value;
		const str = JSON.stringify(serialized);
		const [name, ...namespaceReverse] = serialized.id.slice().reverse();
		const namespace = namespaceReverse.reverse();
		const importMaps = {
			langchain_core: import_map_exports,
			langchain: importMap
		};
		let module = null;
		const optionalImportNamespaceAliases = [namespace.join("/")];
		if (namespace[0] === "langchain_community") optionalImportNamespaceAliases.push(["langchain", ...namespace.slice(1)].join("/"));
		const matchingNamespaceAlias = optionalImportNamespaceAliases.find((alias) => alias in optionalImportsMap);
		if (optionalImportEntrypoints.concat(optionalImportEntrypoints$1).includes(namespace.join("/")) || matchingNamespaceAlias) if (matchingNamespaceAlias !== void 0) module = await optionalImportsMap[matchingNamespaceAlias];
		else throw new Error(`Missing key "${namespace.join("/")}" for ${pathStr} in load(optionalImportsMap={})`);
		else {
			let finalImportMap;
			if (namespace[0] === "langchain" || namespace[0] === "langchain_core") {
				finalImportMap = importMaps[namespace[0]];
				namespace.shift();
			} else throw new Error(`Invalid namespace: ${pathStr} -> ${str}`);
			if (namespace.length === 0) throw new Error(`Invalid namespace: ${pathStr} -> ${str}`);
			let importMapKey;
			do {
				importMapKey = namespace.join("__");
				if (importMapKey in finalImportMap) break;
				else namespace.pop();
			} while (namespace.length > 0);
			if (importMapKey in finalImportMap) module = finalImportMap[importMapKey];
		}
		if (typeof module !== "object" || module === null) throw new Error(`Invalid namespace: ${pathStr} -> ${str}`);
		const builder = module[name] ?? Object.values(module).find((v) => typeof v === "function" && get_lc_unique_name(v) === name);
		if (typeof builder !== "function") throw new Error(`Invalid identifer: ${pathStr} -> ${str}`);
		const kwargs = await reviver.call({
			...this,
			path: [...path, "kwargs"]
		}, serialized.kwargs);
		if (serialized.type === "constructor") {
			const instance = new builder(mapKeys(kwargs, keyFromJson, combineAliasesAndInvert(builder)));
			Object.defineProperty(instance.constructor, "name", { value: name });
			return instance;
		} else throw new Error(`Invalid type: ${pathStr} -> ${str}`);
	} else if (typeof value === "object" && value !== null) if (Array.isArray(value)) return Promise.all(value.map((v, i) => reviver.call({
		...this,
		path: [...path, `${i}`]
	}, v)));
	else return Object.fromEntries(await Promise.all(Object.entries(value).map(async ([key, value$1]) => [key, await reviver.call({
		...this,
		path: [...path, key]
	}, value$1)])));
	return value;
}
async function load(text, mappings) {
	const json = JSON.parse(text);
	return reviver.call({ ...mappings }, json);
}

//#endregion
export { load };
//# sourceMappingURL=index.js.map