feat: support conditions with "!"

readme.md

@@ -340,6 +340,15 @@ resolve.exports(pkg, '.', {
 //=> ["./$worker.js"]
 ```
 
+If you want to remove a condition, you can use the `!` prefix. For example, you only need `"types"`:
+
+```js
+resolve.exports(pkg, '.', {
+  conditions: ['!default', '!import', '!node', 'types']
+});
+// Conditions: ["types"]
+```
+
 #### options.unsafe
 Type: `boolean` <br>
 Default: `false`

src/utils.ts

@@ -13,9 +13,16 @@ export function throws(name: string, entry: Entry, condition?: number): never {
 }
 
 export function conditions(options: t.Options): Set<t.Condition> {
-	let out = new Set([ 'default', ...options.conditions || [] ]);
+	let out = new Set(['default']);
 	options.unsafe || out.add(options.require ? 'require' : 'import');
 	options.unsafe || out.add(options.browser ? 'browser' : 'node');
+	for (const condition of options.conditions || []) {
+		if (condition.startsWith('!')) {
+			out.delete(condition.slice(1));
+		} else {
+			out.add(condition);
+		}
+	}
 	return out;
 }
 

test/utils.ts

@@ -77,12 +77,12 @@ describe('$.conditions', it => {
 
 	it('option.conditions', () => {
 		let output = run({ conditions: ['foo', 'bar'] });
-		assert.equal(output, ['default', 'foo', 'bar', 'import', 'node']);
+		assert.equal(output, ['default', 'import', 'node', 'foo', 'bar']);
 	});
 
 	it('option.conditions :: order', () => {
 		let output = run({ conditions: ['node', 'import', 'foobar'] });
-		assert.equal(output, ['default', 'node', 'import', 'foobar']);
+		assert.equal(output, ['default', 'import', 'node', 'foobar']);
 	});
 
 	it('option.conditions :: unsafe', () => {
@@ -92,22 +92,47 @@ describe('$.conditions', it => {
 
 	it('option.conditions :: browser', () => {
 		let output = run({ browser: true, conditions: ['foo', 'bar'] });
-		assert.equal(output, ['default', 'foo', 'bar', 'import', 'browser']);
+		assert.equal(output, ['default', 'import', 'browser', 'foo', 'bar']);
 	});
 
 	it('option.conditions :: browser :: order', () => {
 		let output = run({ browser: true, conditions: ['browser', 'foobar'] });
-		assert.equal(output, ['default', 'browser', 'foobar', 'import']);
+		assert.equal(output, ['default', 'import', 'browser', 'foobar']);
 	});
 
 	it('option.conditions :: require', () => {
 		let output = run({ require: true, conditions: ['foo', 'bar'] });
-		assert.equal(output, ['default', 'foo', 'bar', 'require', 'node']);
+		assert.equal(output, ['default', 'require', 'node', 'foo', 'bar']);
 	});
 
 	it('option.conditions :: require :: order', () => {
 		let output = run({ require: true, conditions: ['require', 'foobar'] });
-		assert.equal(output, ['default', 'require', 'foobar', 'node']);
+		assert.equal(output, ['default', 'require', 'node', 'foobar']);
+	});
+
+	it('option.conditions :: negate', () => {
+		let output = run({ conditions: ['!import'] });
+		assert.equal(output, ['default', 'node']);
+	});
+
+	it('option.conditions :: negate :: all', () => {
+		let output = run({ conditions: ['!default', '!import', '!node', 'types'] });
+		assert.equal(output, ['types']);
+	});
+
+	it('option.conditions :: negate :: require', () => {
+		let output = run({ require: true, conditions: ['!node', 'deno'] });
+		assert.equal(output, ['default', 'require', 'deno']);
+	});
+
+	it('option.conditions :: negate :: require', () => {
+		let output = run({ browser: true, conditions: ['!browser'] });
+		assert.equal(output, ['default', 'import']);
+	});
+
+	it('option.conditions :: negate :: unsafe', () => {
+		let output = run({ unsafe: true, conditions: ['!foo', 'bar'] });
+		assert.equal(output, ['default', 'bar']);
 	});
 });