feat(internal): isFile

Signed-off-by: Lexus Drumgold <unicornware@flexdevelopment.llc>

src/internal/__tests__/is-file.spec.ts

@@ -0,0 +1,27 @@
+/**
+ * @file Unit Tests - isFile
+ * @module tsconfig-utils/internal/tests/unit/isFile
+ */
+
+import testSubject from '../is-file'
+
+describe('unit:internal/isFile', () => {
+  it('should return false if id does not exist', () => {
+    // Arrange
+    const cases: Parameters<typeof testSubject>[] = [
+      ['file.mjs'],
+      ['node_modules/@flex-development/mkbuild/dist/index.mjs/package.json']
+    ]
+
+    // Act + Expect
+    cases.forEach(([id]) => expect(testSubject(id)).to.be.false)
+  })
+
+  it('should return false if id is directory id', () => {
+    expect(testSubject('src')).to.be.false
+  })
+
+  it('should return true if id is file id', () => {
+    expect(testSubject('src/index.ts')).to.be.true
+  })
+})

src/internal/index.ts

@@ -4,6 +4,7 @@
  */
 
 export { default as isDirectory } from './is-directory'
+export { default as isFile } from './is-file'
 export { default as validateFunction } from './validate-function'
 export { default as validateString } from './validate-string'
 export { default as validateURLString } from './validate-url-string'

src/internal/is-file.ts

@@ -0,0 +1,25 @@
+/**
+ * @file Internal - isFile
+ * @module tsconfig-utils/internal/isFile
+ */
+
+import fs from 'node:fs'
+import type { URL } from 'node:url'
+import validateURLString from './validate-url-string'
+
+/**
+ * Checks if a file exists at the given module `id`.
+ *
+ * @param {URL | string} id - Module id to evaluate
+ * @return {boolean} `true` if file exists at `id`
+ */
+const isFile = (id: URL | string): boolean => {
+  try {
+    validateURLString(id, 'id')
+    return fs.statSync(id, { throwIfNoEntry: false })?.isFile() ?? false
+  } catch {
+    return false
+  }
+}
+
+export default isFile