feat(lib): isAbsolute

Signed-off-by: Lexus Drumgold <[email protected]>

src/lib/__tests__/is-absolute.spec.ts

@@ -0,0 +1,77 @@
+/**
+ * @file Unit Tests - isAbsolute
+ * @module pathe/lib/tests/unit/isAbsolute
+ * @see https://github.com/nodejs/node/blob/main/test/parallel/test-path-isabsolute.js
+ */
+
+import { posix, win32 } from 'node:path'
+import testSubject from '../is-absolute'
+
+describe('unit:lib/isAbsolute', () => {
+  it('should return false if path is not absolute', () => {
+    // Arrange
+    const cases: Parameters<typeof testSubject>[] = [[''], ['./baz'], ['bar/']]
+
+    // Act + Expect
+    cases.forEach(([path]) => {
+      expect(testSubject(path)).to.equal(posix.isAbsolute(path))
+    })
+  })
+
+  it('should return true if path is absolute', () => {
+    // Arrange
+    const cases: Parameters<typeof testSubject>[] = [
+      ['/home/foo'],
+      ['/home/foo/..'],
+      [posix.sep]
+    ]
+
+    // Act + Expect
+    cases.forEach(([path]) => {
+      expect(testSubject(path)).to.equal(posix.isAbsolute(path))
+    })
+  })
+
+  describe('windows', () => {
+    it('should return false if path is not absolute', () => {
+      // Arrange
+      const cases: Parameters<typeof testSubject>[] = [
+        [''],
+        ['C:cwd/another'],
+        ['C:cwd\\another'],
+        ['c'],
+        ['c:'],
+        ['directory/directory'],
+        ['directory\\directory']
+      ]
+
+      // Act + Expect
+      cases.forEach(([path]) => {
+        expect(testSubject(path)).to.equal(win32.isAbsolute(path))
+      })
+    })
+
+    it('should return true if path is absolute', () => {
+      // Arrange
+      const cases: Parameters<typeof testSubject>[] = [
+        ['//server'],
+        ['//server/file'],
+        ['\\\\server'],
+        ['\\\\server\\file'],
+        ['C:/Users/'],
+        ['C:\\Users\\'],
+        ['c:/'],
+        ['c://'],
+        ['c:\\'],
+        [posix.sep.repeat(2)],
+        [posix.sep],
+        [win32.sep.repeat(2)]
+      ]
+
+      // Act + Expect
+      cases.forEach(([path]) => {
+        expect(testSubject(path)).to.equal(win32.isAbsolute(path))
+      })
+    })
+  })
+})

src/lib/index.ts

@@ -7,4 +7,5 @@ export { default as basename } from './basename'
 export { default as delimiter } from './delimiter'
 export { default as dirname } from './dirname'
 export { default as extname } from './extname'
+export { default as isAbsolute } from './is-absolute'
 export { default as sep } from './sep'

src/lib/is-absolute.ts

@@ -0,0 +1,30 @@
+/**
+ * @file isAbsolute
+ * @module pathe/lib/isAbsolute
+ */
+
+import ensurePosix from '#src/internal/ensure-posix'
+import isDrivePath from '#src/internal/is-drive-path'
+import isSep from '#src/internal/is-sep'
+import validateString from '#src/internal/validate-string'
+
+/**
+ * Determines if a path is an absolute path.
+ *
+ * @param {string} path - Path to evaluate
+ * @return {boolean} `true` if `path` is absolute
+ * @throws {TypeError} If `path` is not a string
+ */
+const isAbsolute = (path: string): boolean => {
+  validateString(path, 'path')
+
+  // exit early if path is empty string
+  if (path.length === 0) return false
+
+  // ensure path meets posix standards
+  path = ensurePosix(path)
+
+  return isSep(path.charAt(0)) || (isDrivePath(path) && isSep(path.charAt(2)))
+}
+
+export default isAbsolute