@langchain/langgraph/dist/graph/zod/state.js

LangGraph

import { BinaryOperatorAggregate } from "../../channels/binop.js";
import { LastValue } from "../../channels/last_value.js";
// eslint-disable-next-line @typescript-eslint/no-explicit-any
const META_MAP = new WeakMap();
function isZodType(value) {
    return (typeof value === "object" &&
        value != null &&
        "_parse" in value &&
        typeof value._parse === "function");
}
/**
 * @internal
 */
export function isZodDefault(value) {
    return (isZodType(value) &&
        "removeDefault" in value &&
        typeof value.removeDefault === "function");
}
/**
 * @internal
 */
export function isAnyZodObject(value) {
    return (isZodType(value) &&
        "partial" in value &&
        typeof value.partial === "function");
}
export function withLangGraph(schema, meta) {
    if (meta.reducer && !meta.default) {
        const defaultValue = isZodDefault(schema)
            ? schema._def.defaultValue
            : undefined;
        if (defaultValue != null) {
            // eslint-disable-next-line no-param-reassign
            meta.default = defaultValue;
        }
    }
    META_MAP.set(schema, meta);
    return schema;
}
export function getMeta(schema) {
    return META_MAP.get(schema);
}
export function extendMeta(schema, update) {
    const existingMeta = getMeta(schema);
    const newMeta = update(existingMeta);
    META_MAP.set(schema, newMeta);
}
export function getChannelsFromZod(schema) {
    const channels = {};
    for (const key in schema.shape) {
        if (Object.prototype.hasOwnProperty.call(schema.shape, key)) {
            const keySchema = schema.shape[key];
            const meta = getMeta(keySchema);
            if (meta?.reducer) {
                channels[key] = new BinaryOperatorAggregate(meta.reducer.fn, meta.default);
            }
            else {
                channels[key] = new LastValue();
            }
        }
    }
    return channels;
}
const ZOD_TYPE_CACHE = {};
const ZOD_DESCRIPTION_PREFIX = "lg:";
export function applyZodPlugin(schema, actions) {
    const cacheKey = [
        `reducer:${actions.reducer ?? false}`,
        `jsonSchemaExtra:${actions.jsonSchemaExtra ?? false}`,
        `partial:${actions.partial ?? false}`,
    ].join("|");
    ZOD_TYPE_CACHE[cacheKey] ??= new WeakMap();
    const cache = ZOD_TYPE_CACHE[cacheKey];
    if (cache.has(schema))
        return cache.get(schema);
    let shape = schema.extend({
        ...Object.fromEntries(Object.entries(schema.shape).map(([key, input]) => {
            const meta = getMeta(input);
            let output = actions.reducer ? meta?.reducer?.schema ?? input : input;
            if (actions.jsonSchemaExtra) {
                const strMeta = JSON.stringify({
                    ...meta?.jsonSchemaExtra,
                    description: output.description ?? input.description,
                });
                if (strMeta !== "{}") {
                    output = output.describe(`${ZOD_DESCRIPTION_PREFIX}${strMeta}`);
                }
            }
            return [key, output];
        })),
    });
    // using zObject.extend() will set `unknownKeys` to `passthrough`
    // which trips up `zod-to-json-schema`
    if ("_def" in shape &&
        shape._def != null &&
        typeof shape._def === "object" &&
        "unknownKeys" in shape._def) {
        shape._def.unknownKeys = "strip";
    }
    if (actions.partial)
        shape = shape.partial();
    cache.set(schema, shape);
    return shape;
}
export function applyExtraFromDescription(schema) {
    if (Array.isArray(schema)) {
        return schema.map(applyExtraFromDescription);
    }
    if (typeof schema === "object" && schema != null) {
        const output = Object.fromEntries(Object.entries(schema).map(([key, value]) => [
            key,
            applyExtraFromDescription(value),
        ]));
        if ("description" in output &&
            typeof output.description === "string" &&
            output.description.startsWith(ZOD_DESCRIPTION_PREFIX)) {
            const strMeta = output.description.slice(ZOD_DESCRIPTION_PREFIX.length);
            delete output.description;
            Object.assign(output, JSON.parse(strMeta));
        }
        return output;
    }
    return schema;
}
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