> For the complete documentation index, see [llms.txt](https://yamoo9.gitbook.io/typescript/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yamoo9.gitbook.io/typescript/ts-vs-es6/block-scope.md).

# 블록 영역 변수, 상수 선언

ES6부터 **`let`, `const` 키워드를 사용해 변수, 상수를 정의**할 수 있습니다. TypeScript 또한 마찬가지로 활용 가능합니다. `let` 변수는 `var` 변수가 불러오는 문제점(중복 선언, 호이스트에 따른 의도치 않은 동작 등)을 훌륭하게 해결 하므로 사용이 권장됩니다. 그리고 `let`, `const` 키워드를 사용하면 블록 스코프(Block Scope)를 사용할 수 있습니다.

**작성 코드:**

{% code title="TypeScript" %}

```typescript
let context = document.querySelector('html');

{
  let context = document.querySelector('body');
  console.log('블록문 내부 context = ', context);
}

console.log('글로벌 context = ', context);
```

{% endcode %}

**컴파일 코드:**

{% code title="JavaScript" %}

```javascript
var context = document.querySelector('html');

{
  var context_1 = document.querySelector('body');
  console.log('블록문 내부 context = ', context_1);
}

console.log('글로벌 context = ', context);
```

{% endcode %}

{% embed url="<https://slides.com/yamoo9/es6#/1>" %}


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