# Sets preference level for triple slash directives versus ES6-style import declarations (`triple-slash-reference`)

Use of triple-slash reference type directives is discouraged in favor of the newer `import` style. This rule allows you to ban use of `/// <reference path="" />`, `/// <reference types="" />`, or `/// <reference lib="" />` directives.

Consider using this rule in place of [`no-triple-slash-reference`](./no-triple-slash-reference.md) which has been deprecated.

## Rule Details

With `{ "path": "never", "types": "never", "lib": "never" }` options set, the following will all be **incorrect** usage:

```ts
/// <reference path="foo" />
/// <reference types="bar" />
/// <reference lib="baz" />
```

Examples of **incorrect** code for the `{ "types": "prefer-import" }` option. Note that these are only errors when **both** styles are used for the **same** module:

```ts
/// <reference types="foo" />
import * as foo from 'foo';
```

```ts
/// <reference types="foo" />
import foo = require('foo');
```

With `{ "path": "always", "types": "always", "lib": "always" }` options set, the following will all be **correct** usage:

```ts
/// <reference path="foo" />
/// <reference types="bar" />
/// <reference lib="baz" />
```

Examples of **correct** code for the `{ "types": "prefer-import" }` option:

```ts
import * as foo from 'foo';
```

```ts
import foo = require('foo');
```

## When To Use It

If you want to ban use of one or all of the triple slash reference directives, or any time you might use triple-slash type reference directives and ES6 import declarations in the same file.

## When Not To Use It

If you want to use all flavors of triple slash reference directives.

## Compatibility

- TSLint: [no-reference](http://palantir.github.io/tslint/rules/no-reference/)
- TSLint: [no-reference-import](https://palantir.github.io/tslint/rules/no-reference-import/)