From 295db2a41b1c1dade4cfee3482d9c25de78fd33e Mon Sep 17 00:00:00 2001
From: mrmlnc <mrmlnc@yandex-team.ru>
Date: Sat, 26 Jun 2021 17:38:29 +0300
Subject: [PATCH] feat(utils): add uilities for obtaining patterns relative to
 the current directory

---
 src/utils/pattern.spec.ts | 46 +++++++++++++++++++++++++++++++++++++++
 src/utils/pattern.ts      | 26 ++++++++++++++++++++++
 2 files changed, 72 insertions(+)

diff --git a/src/utils/pattern.spec.ts b/src/utils/pattern.spec.ts
index 8b56187b..59983e14 100644
--- a/src/utils/pattern.spec.ts
+++ b/src/utils/pattern.spec.ts
@@ -257,6 +257,52 @@ describe('Utils → Pattern', () => {
 		});
 	});
 
+	describe('.getPatternsInsideCurrentDirectory', () => {
+		it('should return patterns', () => {
+			const expected: Pattern[] = ['.', './*', '*', 'a/*'];
+
+			const actual = util.getPatternsInsideCurrentDirectory(['.', './*', '*', 'a/*', '..', '../*', './..', './../*']);
+
+			assert.deepStrictEqual(actual, expected);
+		});
+	});
+
+	describe('.getPatternsOutsideCurrentDirectory', () => {
+		it('should return patterns', () => {
+			const expected: Pattern[] = ['..', '../*', './..', './../*'];
+
+			const actual = util.getPatternsOutsideCurrentDirectory(['.', './*', '*', 'a/*', '..', '../*', './..', './../*']);
+
+			assert.deepStrictEqual(actual, expected);
+		});
+	});
+
+	describe('.isPatternRelatedToParentDirectory', () => {
+		it('should be `false` when the pattern refers to the current directory', () => {
+			const actual = util.isPatternRelatedToParentDirectory('.');
+
+			assert.ok(!actual);
+		});
+
+		it('should be `true` when the pattern equals to `..`', () => {
+			const actual = util.isPatternRelatedToParentDirectory('..');
+
+			assert.ok(actual);
+		});
+
+		it('should be `true` when the pattern starts with `..` segment', () => {
+			const actual = util.isPatternRelatedToParentDirectory('../*');
+
+			assert.ok(actual);
+		});
+
+		it('should be `true` when the pattern starts with `./..` segment', () => {
+			const actual = util.isPatternRelatedToParentDirectory('./../*');
+
+			assert.ok(actual);
+		});
+	});
+
 	describe('.getBaseDirectory', () => {
 		it('should returns base directory', () => {
 			const expected = 'root';
diff --git a/src/utils/pattern.ts b/src/utils/pattern.ts
index 9801e138..6190b66f 100644
--- a/src/utils/pattern.ts
+++ b/src/utils/pattern.ts
@@ -81,6 +81,32 @@ export function getPositivePatterns(patterns: Pattern[]): Pattern[] {
 	return patterns.filter(isPositivePattern);
 }
 
+/**
+ * Returns patterns that can be applied inside the current directory.
+ *
+ * @example
+ * // ['./*', '*', 'a/*']
+ * getPatternsInsideCurrentDirectory(['./*', '*', 'a/*', '../*', './../*'])
+ */
+export function getPatternsInsideCurrentDirectory(patterns: Pattern[]): Pattern[] {
+	return patterns.filter((pattern) => !isPatternRelatedToParentDirectory(pattern));
+}
+
+/**
+ * Returns patterns to be expanded relative to (outside) the current directory.
+ *
+ * @example
+ * // ['../*', './../*']
+ * getPatternsInsideCurrentDirectory(['./*', '*', 'a/*', '../*', './../*'])
+ */
+export function getPatternsOutsideCurrentDirectory(patterns: Pattern[]): Pattern[] {
+	return patterns.filter(isPatternRelatedToParentDirectory);
+}
+
+export function isPatternRelatedToParentDirectory(pattern: Pattern): boolean {
+	return pattern.startsWith('..') || pattern.startsWith('./..');
+}
+
 export function getBaseDirectory(pattern: Pattern): string {
 	return globParent(pattern, { flipBackslashes: false });
 }