Merge pull request #23 from Designory/fix/check-for-zip-and-diff-binary

Fix - Check for `zip` and `diff` binaries

index.js

@@ -9,9 +9,18 @@ const fs = require('fs-extra');
 const colors = require('colors');
 const parseArgs = require('minimist');
 
+const hasBinary = require('./src/has-binary');
 const diffDirectories = require('./src/gen-diff-object');
 
 (async () => {
+	const has_zip = hasBinary('zip');
+	const has_diff = hasBinary('diff');
+
+	if (!(has_zip && has_diff)) {
+		console.error(`Could not find both "${'zip'.yellow}" and "${'diff'.yellow}" binaries, both of which are required. Exiting.`);
+		process.exit(1);
+	}
+
 	const arg_options = {
 		boolean: [
 			'quiet',

src/has-binary.js

@@ -0,0 +1,32 @@
+const fs = require('fs');
+const path = require('path');
+
+const getPaths = (bin_path) => {
+	const envPath = process.env.PATH || '';
+	const envExt = process.env.PATHEXT || '';
+	return envPath
+		.replace(/["]+/g, '')
+		.split(path.delimiter)
+		.map((chunk) => {
+			return envExt.split(path.delimiter).map((ext) => path.join(chunk, bin_path + ext));
+		})
+		.reduce((a, b) => a.concat(b));
+};
+
+/**
+ * Helper utility to check if a binary exists in our $PATH variable. Used to
+ * see if the user has `zip` installed (and maybe others).
+ * @see https://github.com/springernature/hasbin/blob/5af037b/lib/hasbin.js
+ * @returns {Boolean}
+ */
+const hasBinary = (bin) => {
+	return getPaths(bin).some((filePath) => {
+		try {
+			return fs.statSync(filePath).isFile();
+		} catch (error) {
+			return false;
+		}
+	});
+};
+
+module.exports = hasBinary;