> ## Documentation Index
> Fetch the complete documentation index at: https://docs.wandb.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Why does my Weave TypeScript build fail for CommonJS format?

## `TS1295` and `TS1287`: ECMAScript imports and exports cannot be written in a CommonJS file

If your `tsconfig.json` file sets `"verbatimModuleSyntax": true`, compiling a W\&B Weave CommonJS project (per the [TypeScript SDK integration guide](/weave/guides/integrations/js)) fails with:

```text theme={null}
error TS1295: ECMAScript imports and exports cannot be written in a CommonJS file under 'verbatimModuleSyntax'.
error TS1287: A top-level 'export' modifier cannot be used on value declarations in a CommonJS module when 'verbatimModuleSyntax' is enabled.
```

The setting defaults to `false`, which the TypeScript SDK integration guide assumes.

Set the `verbatimModuleSyntax` field to `false` alongside your CommonJS `module` setting:

```json lines theme={null}
{
  "compilerOptions": {
    "module": "CommonJS",
    "verbatimModuleSyntax": false
  }
}
```

`"verbatimModuleSyntax": false` allows ESM-style `import`/`export` syntax in your source files while TypeScript still emits CommonJS output. For details, see [TypeScript - Verbatim Module Syntax](https://www.typescriptlang.org/tsconfig/#verbatimModuleSyntax).

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