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eslint/no-undef Nursery

What it does

Disallow the use of undeclared variables.

This rule can be disabled for TypeScript code, as the TypeScript compiler enforces this check.

Why is this bad?

It is most likely a potential ReferenceError caused by a misspelling of a variable or parameter name.

Examples

Examples of incorrect code for this rule:

javascript
var foo = someFunction();
var bar = a + 1;

Configuration

This rule accepts a configuration object with the following properties:

typeof

type: boolean

default: false

When set to true, warns on undefined variables used in a typeof expression.

How to use

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

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

References

Released under the MIT License.