pve-eslint/eslint/docs/rules/no-eq-null.md
Dominik Csapak eb39fafa4f first commit
includes a (minimal) working wrapper

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
2020-04-06 15:06:03 +02:00

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Markdown

# Disallow Null Comparisons (no-eq-null)
Comparing to `null` without a type-checking operator (`==` or `!=`), can have unintended results as the comparison will evaluate to true when comparing to not just a `null`, but also an `undefined` value.
```js
if (foo == null) {
bar();
}
```
## Rule Details
The `no-eq-null` rule aims reduce potential bug and unwanted behavior by ensuring that comparisons to `null` only match `null`, and not also `undefined`. As such it will flag comparisons to null when using `==` and `!=`.
Examples of **incorrect** code for this rule:
```js
/*eslint no-eq-null: "error"*/
if (foo == null) {
bar();
}
while (qux != null) {
baz();
}
```
Examples of **correct** code for this rule:
```js
/*eslint no-eq-null: "error"*/
if (foo === null) {
bar();
}
while (qux !== null) {
baz();
}
```