Skip to content

eslint/no-implicit-coercion Style

🛠️ An auto-fix is available for this rule.

What it does

Disallows shorthand type conversions using operators like !!, +, ""+ , etc.

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). Default: true

disallowTemplateShorthand

type: boolean

default: false

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

number

type: boolean

default: true

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

string

type: boolean

default: true

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

How to use

To enable this rule using the config file or in the CLI, you can use:

json
{
    "rules": {
        "no-implicit-coercion": "error"
    }
}
bash
oxlint --deny no-implicit-coercion

References

Released under the MIT License.