---
title: Enforce the use of === and !==
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Static Code Analysis (SAST) > SAST
  Rules > Enforce the use of === and !==
---

# Enforce the use of === and !==

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# Important note for users on the following Datadog sites: app.ddog-gov.com, us2.ddog-gov.com

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{% /callout %}

## Metadata{% #metadata %}

**ID:** `typescript-code-style/strict-equals`

**Language:** TypeScript

**Severity:** Notice

**Category:** Best Practices

## Description{% #description %}

In JavaScript, `==` and `!=` comparisons do type coercion, which can be confusing and may introduce potential errors. Use the type-safe equality operators `===` and `!==` instead.

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```typescript
b == c

foobarbaz == true
foobar != 1
plop == undefined
```

```typescript
a == b
a != b
typeof a == 'number'
typeof a == 'number'
'string' != typeof a
true == true
2 == 3
2 == 3
'hello' != 'world'
'hello' != 'world'
a == null
a == null
null != a
true == 1
0 != '1'
'wee' == /wee/
typeof a == 'number'
'string' != typeof a
'hello' != 'world'
2 == 3
true == true
true == null
true != null
null == null
null != null
a
==
b
(a) == b
(a) != b
a == (b)
a != (b)
(a) == (b)
(a == b) == (c)
(a != b) != (c)
a == b;
a!=b;
(a + b) == c;
(a + b)  !=  c;
((1) )  ==  (2);
```

## Compliant Code Examples{% #compliant-code-examples %}

```typescript
'foo' != 'bar'
51 == 42
true == true
foobarbaz == null
typeof foo == 'undefined'
```

```typescript
a === b
a !== b
a === b
a !== null
a === null
a !== null
null === null
null !== null
```
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