diff --git a/docs/preprocessing.md b/docs/preprocessing.md
index 5eb3cdd4..267e11b8 100644
--- a/docs/preprocessing.md
+++ b/docs/preprocessing.md
@@ -71,7 +71,7 @@ The following options can be passed to the preprocessor. None are required:
| `aliases` | `null` | A list of tuples `[alias: string, language: string]` that correlates an `alias` to a `language`
i.e `['cst', 'customLanguage']` means
`<... src="./file.cst">`
`<... lang="cst">`
`<... type="text/customLanguage">`
`<... type="application/customLanguage">`
are treated as `customLanguage`. |
| preserve | `[]` | A `string` list of languages/aliases that shouldn't pass through the preprocessor. (i.e `ld+json`) |
| `defaults` | `{ markup: 'html', script: 'javascript', style: 'css' }` | An `object` that defines the default languages of your components.
i.e: `{ script: 'typescript' }` makes TypeScript the default language, removing the need of adding `lang="ts"` to `script` tags. |
-| `sourceMap` | `true` | If `true`, `svelte-preprocess` generates sourcemap for every language that supports it. |
+| `sourceMap` | `false` | If `true`, `svelte-preprocess` generates sourcemap for every language that supports it. |
##### Configuring preprocessors