feat(exposed/file): adds json

src/exposed/file/index.ts

@@ -0,0 +1 @@
+export { default as json } from './json';

src/exposed/file/json.ts

@@ -0,0 +1,31 @@
+import path from 'path';
+import fs from 'fs-extra';
+import { exists } from '~/utils/file';
+import core from '~/core';
+import { IOfType, TScript } from '~/types';
+import { rejects } from 'errorish';
+
+/**
+ * Reads a JSON `file` and passes it as an argument to a callback `fn`. If the callback returns an object, **`file` will be overwritten** with its contents. `file` can be relative to the project's directory.
+ * @returns A `TScript`, as a function, that won't be executed until called by `kpo` -hence, calling `json` won't have any effect until the returned function is called.
+ */
+export default function json(
+  file: string,
+  fn: (json: IOfType<any>) => IOfType<any> | void | Promise<IOfType<any> | void>
+): TScript {
+  return async function json(): Promise<void> {
+    if (!path.isAbsolute(file)) {
+      const paths = await core.paths();
+      file = path.join(paths.directory, file);
+    }
+
+    await exists(file, { fail: true });
+    const json = await fs.readJSON(file).catch(rejects);
+    const response = await fn(json);
+    if (response) {
+      await fs
+        .writeFile(file, JSON.stringify(response, null, 2))
+        .catch(rejects);
+    }
+  };
+}

src/exposed/index.ts

@@ -1,4 +1,5 @@
 export * from './exec';
+export * from './file';
 export * from './prompts';
 export * from './tags';
 export { default as options } from './options';