@langchain/core/dist/utils/json_schema.js

Core LangChain.js abstractions and schemas

import { zodToJsonSchema } from "zod-to-json-schema";
import { dereference } from "@cfworker/json-schema";
import { isZodSchema } from "./types/is_zod_schema.js";
export { deepCompareStrict, Validator } from "@cfworker/json-schema";
/**
 * Converts a Zod schema or JSON schema to a JSON schema.
 * @param schema - The schema to convert.
 * @returns The converted schema.
 */
export function toJsonSchema(schema) {
    if (isZodSchema(schema)) {
        return zodToJsonSchema(schema);
    }
    return schema;
}
/**
 * Validates if a JSON schema validates only strings. May return false negatives in some edge cases
 * (like recursive or unresolvable refs).
 *
 * @param schema - The schema to validate.
 * @returns `true` if the schema validates only strings, `false` otherwise.
 */
export function validatesOnlyStrings(schema) {
    // Null, undefined, or empty schema
    if (!schema ||
        typeof schema !== "object" ||
        Object.keys(schema).length === 0 ||
        Array.isArray(schema)) {
        return false; // Validates anything, not just strings
    }
    // Explicit type constraint
    if ("type" in schema) {
        if (typeof schema.type === "string") {
            return schema.type === "string";
        }
        if (Array.isArray(schema.type)) {
            // not sure why someone would do `"type": ["string"]` or especially `"type": ["string",
            // "string", "string", ...]` but we're not here to judge
            return schema.type.every((t) => t === "string");
        }
        return false; // Invalid or non-string type
    }
    // Enum with only string values
    if ("enum" in schema) {
        return (Array.isArray(schema.enum) &&
            schema.enum.length > 0 &&
            schema.enum.every((val) => typeof val === "string"));
    }
    // String constant
    if ("const" in schema) {
        return typeof schema.const === "string";
    }
    // Schema combinations
    if ("allOf" in schema && Array.isArray(schema.allOf)) {
        // If any subschema validates only strings, then the overall schema validates only strings
        return schema.allOf.some((subschema) => validatesOnlyStrings(subschema));
    }
    if (("anyOf" in schema && Array.isArray(schema.anyOf)) ||
        ("oneOf" in schema && Array.isArray(schema.oneOf))) {
        const subschemas = ("anyOf" in schema ? schema.anyOf : schema.oneOf);
        // All subschemas must validate only strings
        return (subschemas.length > 0 &&
            subschemas.every((subschema) => validatesOnlyStrings(subschema)));
    }
    // We're not going to try on this one, it's too complex - we just assume if it has a "not" key and hasn't matched one of the above checks, it's not a string schema.
    if ("not" in schema) {
        return false; // The not case can validate non-strings
    }
    if ("$ref" in schema && typeof schema.$ref === "string") {
        const ref = schema.$ref;
        const resolved = dereference(schema);
        if (resolved[ref]) {
            return validatesOnlyStrings(resolved[ref]);
        }
        return false;
    }
    // ignore recursive refs and other cases where type is omitted for now
    // ignore other cases for now where type is omitted
    return false;
}