# Cannot redeclare block-scoped variable 'name'

Source: https://tpiros.dev/blog/cannot-redeclare-block-scoped-variable-name

# The problem

This error has tripped me up more times than I'd like to admit:

```
[ts] Cannot redeclare block-scoped variable 'name'.
```

It fires when you try to declare a variable called `name`:

```typescript
const name = 'John';
```

# The explanation

Here's the thing: it's not a bug. TypeScript pulls in DOM typings for the global execution environment, and there's already a `name` property sitting on the global `window` object. Don't believe me? Open your browser console and type this:

```typescript
'name' in window ? 'property exists' : 'property does not exist'; // property exists
```

(You can also check the property's value but it'll return an empty string: `window.name; // ""`.)

# The solution

Three ways to squash this:

1. Rename the variable to something other than `name`.
2. Turn your file into a TypeScript module by adding an empty `export {};`:

```typescript

const name = 'John';
```

1. Strip out the DOM typings from your compiler options. Drop an explicit `lib` property into `tsconfig.json`:

```json
{
  "compilerOptions": {
    "lib": ["es6"]
  }
}
```

Pick any of those three and the error vanishes. Back to writing TypeScript.