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ban-ts-comment

Disallow @ts-<directive> comments or require descriptions after directives.

TypeScript provides several directive comments that can be used to alter how it processes files. Using these to suppress TypeScript compiler errors reduces the effectiveness of TypeScript overall. Instead, it's generally better to correct the types of code, to make directives unnecessary.

The directive comments supported by TypeScript are:

// @ts-expect-error
// @ts-ignore
// @ts-nocheck
// @ts-check

This rule lets you set which directive comments you want to allow in your codebase.

.eslintrc.cjs
module.exports = {
"rules": {
"@typescript-eslint/ban-ts-comment": "error"
}
};

Options

This rule accepts an options object with the following properties:

type DirectiveConfigSchema =
| boolean
| "allow-with-description"
| {
descriptionFormat?: string;
};

interface Options {
"ts-expect-error"?: DirectiveConfigSchema;
"ts-ignore"?: DirectiveConfigSchema;
"ts-nocheck"?: DirectiveConfigSchema;
"ts-check"?: DirectiveConfigSchema;
minimumDescriptionLength?: number;
}

const defaultOptions: Options = [
{
"ts-expect-error": "allow-with-description",
"ts-ignore": true,
"ts-nocheck": true,
"ts-check": false,
minimumDescriptionLength: 3,
},
];

By default, only @ts-check is allowed, as it enables rather than suppresses errors.

ts-expect-error, ts-ignore, ts-nocheck, ts-check directives

A value of true for a particular directive means that this rule will report if it finds any usage of said directive.

if (false) {
// @ts-ignore: Unreachable code error
console.log('hello');
}
if (false) {
/*
@ts-ignore: Unreachable code error
*/
console.log('hello');
}

allow-with-description

A value of 'allow-with-description' for a particular directive means that this rule will report if it finds a directive that does not have a description following the directive (on the same line).

For example, with { 'ts-expect-error': 'allow-with-description' }:

if (false) {
// @ts-expect-error
console.log('hello');
}
if (false) {
/* @ts-expect-error */
console.log('hello');
}

descriptionFormat

For each directive type, you can specify a custom format in the form of a regular expression. Only description that matches the pattern will be allowed.

For example, with { 'ts-expect-error': { descriptionFormat: '^: TS\\d+ because .+$' } }:

// @ts-expect-error: the library definition is wrong
const a = doSomething('hello');

minimumDescriptionLength

Use minimumDescriptionLength to set a minimum length for descriptions when using the allow-with-description option for a directive.

For example, with { 'ts-expect-error': 'allow-with-description', minimumDescriptionLength: 10 } the following pattern is:

if (false) {
// @ts-expect-error: TODO
console.log('hello');
}

When Not To Use It

If you want to use all of the TypeScript directives.

Further Reading

Resources