# no-blob-to-file

📝 Disallow unnecessary `Blob` to `File` conversion.

💼 This rule is enabled in the following [configs](https://github.com/sindresorhus/eslint-plugin-unicorn#recommended-config): ✅ `recommended`, ☑️ `unopinionated`.

💡 This rule is manually fixable by [editor suggestions](https://eslint.org/docs/latest/use/core-concepts#rule-suggestions).

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`File` objects implement the `Blob` interface. Converting a `Blob` to a `File` just to pass it to APIs that already accept a `Blob` is unnecessary.

This rule currently checks a narrow pattern: a standalone, comment-free `const` initialized with `new File([blob], 'filename')` and used once in `URL.createObjectURL()`, `FormData#append()`, or `FormData#set()`. The `blob` value must be an earlier `const` initialized with `new Blob()`, `new Blob(parts)`, or `new File(parts, name)` without type options. For `FormData`, the receiver must be a `const` initialized with `new FormData()`.

## Examples

```js
// ❌
const blob = new Blob();
const file = new File([blob], 'image.jpg');
URL.createObjectURL(file);

// ✅
URL.createObjectURL(blob);
```

```js
// ❌
const blob = new Blob();
const formData = new FormData();
const file = new File([blob], 'image.jpg');
formData.append('file', file);

// ✅
formData.append('file', blob, 'image.jpg');
```

```js
// ❌
const blob = new Blob();
const formData = new FormData();
const file = new File([blob], 'image.jpg');
formData.set('file', file);

// ✅
formData.set('file', blob, 'image.jpg');
```