# TypeError: Class extends value undefined is not a constructor or null with Elastic Search Library with TypeScript

**URL:** <https://discuss.elastic.co/t/typeerror-class-extends-value-undefined-is-not-a-constructor-or-null-with-elastic-search-library-with-typescript/338984>\
**Category:** Elasticsearch\
**Created:** [July 22, 2023, 9:28am UTC](https://discuss.elastic.co/t/typeerror-class-extends-value-undefined-is-not-a-constructor-or-null-with-elastic-search-library-with-typescript/338984 "2023-07-22T09:28:31Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tanmay\_Sharma](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tanmay_sharma/32/123756_2.png) [@Tanmay\_Sharma](https://discuss.elastic.co/u/Tanmay_Sharma)\
**Post date:** [July 22, 2023, 9:28am UTC](https://discuss.elastic.co/t/typeerror-class-extends-value-undefined-is-not-a-constructor-or-null-with-elastic-search-library-with-typescript/338984/1 "2023-07-22T09:28:31Z")

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Hello Everyone,  
While using the Elastic Search Library with TypeScript in Svelte giving unknown TypeError:

```auto
import { Client } from "@elastic/elasticsearch";
    import * as fs from "fs";

    const client = new Client({
        node: "https://localhost:9200",
        auth: {
            username: "elastic",
            password: "<Password>",
        },
        tls: {
            ca: fs.readFileSync("./src/lib/http_ca.crt", "utf-8"),
            rejectUnauthorized: false,
        },
    });

```

This error is occuring while using Elasticsearch library in TypeScript.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [August 19, 2023, 9:29am UTC](https://discuss.elastic.co/t/typeerror-class-extends-value-undefined-is-not-a-constructor-or-null-with-elastic-search-library-with-typescript/338984/2 "2023-08-19T09:29:07Z")

</div>

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