---
url: /docs/guide/usage/linter/rules/eslint/no-implicit-coercion.md
---

### What it does

Disallow shorthand type conversions using operators like `!!`, unary `+`, and `"" +`.

### Why is this bad?

Implicit type coercions using operators can be less clear than using explicit
type conversion functions like `Boolean()`, `Number()`, and `String()`.
Using explicit conversions makes the intent clearer and the code more readable.

### Examples

Examples of **incorrect** code for this rule:

```javascript
var b = !!foo;
var n = +foo;
var s = "" + foo;
```

Examples of **correct** code for this rule:

```javascript
var b = Boolean(foo);
var n = Number(foo);
var s = String(foo);
```

## Configuration

This rule accepts a configuration object with the following properties:

### allow

type: `string[]`

List of operators to allow. Valid values: `"!!"`, `"~"`, `"+"`, `"-"`, `"- -"`, `"*"`

### boolean

type: `boolean`

default: `true`

When `true`, warns on implicit boolean coercion (e.g., `!!foo`).

### disallowTemplateShorthand

type: `boolean`

default: `false`

When `true`, disallows using template literals for string coercion (e.g., `` `${foo}` ``).

### number

type: `boolean`

default: `true`

When `true`, warns on implicit number coercion (e.g., `+foo`).

### string

type: `boolean`

default: `true`

When `true`, warns on implicit string coercion (e.g., `"" + foo`).

## How to use

## Version

This rule was added in v1.33.0.

## References