eslint/no-implicit-coercion Style

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:

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

Examples of correct code for this rule:

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

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

Config (.oxlintrc.json)

{
  "rules": {
    "no-implicit-coercion": "error"
  }
}

CLI

oxlint --deny no-implicit-coercion

References

• Rule Source