[New] prefer-default-export: add "target" option

[azyzz228]

Solution for #2600.

I have added new option for the prefer-default-export that will check any exporting file to have a default export.

schema:

"import/prefer-default-export": [
 	( "off" | "warn" | "error" ),
	{ "target": "single" | "any" } // default is "single"
]

Config options

• single (current implementation of the rule, I did not change anything here): When there is only a single export from a module, prefer using default export over named export.

All examples from below are from the rule descriptions.

Considered warnings:

// bad.js

// There is only a single module export and it's a named export.
export const foo = 'foo';

The following patterns are not warnings:

// good1.js

// There is a default export.
export const foo = 'foo';
const bar = 'bar';
export default bar;

// good2.js

// There is more than one named export in the module.
export const foo = 'foo';
export const bar = 'bar';

// good3.js

// There is more than one named export in the module
const foo = 'foo';
const bar = 'bar';
export { foo, bar }

// good4.js

// There is a default export.
const foo = 'foo';
export { foo as default }

// export-star.js

// Any batch export will disable this rule. The remote module is not inspected.
export * from './other-module'

newly added config option:

• any: any exporting file must contain default export.

No warnings:

//has default export
export default function bar() {};

// has default export
let foo;
export { foo as default }

//contains multiple exports AND default export
export const a = 5;
export function bar(){};
let foo;
export { foo as default }`

// does not contain any exports => file is not checked by the rule
import * as foo from './foo';

// export-star.js

// Any batch export will disable this rule. The remote module is not inspected.
export * from './other-module'

Following are considered as warnings:

//has 2 named exports, but no default export
export const foo = 'foo';
export const bar = 'bar';

// does not have default export
let foo, bar;
export { foo, bar }

// does not have default export
export { a, b } from "foo.js"

// does not have default export
let item;
export const foo = item;
export { item };`

Questions

I am not sure how to migrate the test cases below to new option "any". I do not understand what's going on here and what is exported.

export const { foo, bar } = item;

export const { foo, bar: baz } = item;

export const { foo: { bar, baz } } = item;

export const [a, b] = item;

I will update docs after your review.

[codecov]

Codecov Report

Base: 95.28% // Head: 95.29% // Increases project coverage by +0.01% 🎉

Coverage data is based on head (93609f2) compared to base (f4f305b).
Patch coverage: 100.00% of modified lines in pull request are covered.

❗ Current head 93609f2 differs from pull request most recent head 922819f. Consider uploading reports for the commit 922819f to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2602      +/-   ##
==========================================
+ Coverage   95.28%   95.29%   +0.01%     
==========================================
  Files          68       68              
  Lines        2947     2954       +7     
  Branches      998     1002       +4     
==========================================
+ Hits         2808     2815       +7     
  Misses        139      139              

Impacted Files	Coverage Δ
src/rules/prefer-default-export.js	100.00% <100.00%> (ø)
resolvers/node/index.js	96.96% <0.00%> (-0.09%)	⬇️

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