feat(exposed/exists): adds exists

src/exposed/file/exists.ts

@@ -0,0 +1,17 @@
+import path from 'path';
+import core from '~/core';
+import { exists as _exists } from '~/utils/file';
+
+/**
+ * Verifies `file` exists and throws if it doesn't. `file` can be either a file or a directory, and be relative to the project's directory.
+ * @returns A `TScript`, as a function, that won't be executed until called by `kpo` -hence, calling `exists` won't have any effect until the returned function is called.
+ */
+export default function exists(file: string) {
+  return async function exists(): Promise<void> {
+    if (!path.isAbsolute(file)) {
+      const paths = await core.paths();
+      file = path.join(paths.directory, file);
+    }
+    await _exists(file, { fail: true });
+  };
+}

src/exposed/file/index.ts

@@ -1 +1,2 @@
 export { default as json } from './json';
+export { default as exists } from './exists';