Add support for the --check parameter

Author: darkriszty

README.md

@@ -33,7 +33,9 @@ The tipical location of the installed extension (your actual version might diffe
 Available features from the command line:
 - To format a file: `npm run --silent prettify-md < input.md`.
 - To format a file and save the output: `npm run --silent prettify-md < input.md > output.md`.
-- To check whether a file is prettyfied or not: `npm run --silent prettify-md --check < input.md`. This will fail if the file is not prettyfied.
+- To check whether a file is prettyfied or not: `npm run --silent check-md < input.md`. This will fail with an exception and return code `1` if the file is not prettyfied.
+
+> Note: the `--silent` switch sets the npm log level to silent, which is useful to hide the executed file name and concentrate on the actual output.
 
 ## Extension Settings
 

cli/cliPrettify.ts

@@ -23,6 +23,12 @@ export class CliPrettify {
         return prettyfier.formatTables(text);
     }
 
+    public static check(text: string): void {
+        if (this.prettify(text) !== text) {
+            throw new Error("The input file is not prettyfied!");
+        }
+    }
+
     private static createPrettyfier(): MultiTablePrettyfier {
         const logger = new ConsoleLogger();
         return new MultiTablePrettyfier(

cli/index.ts

@@ -1,4 +1,10 @@
 import { CliPrettify } from "./cliPrettify";
 import { InputReader } from "./inputReader";
 
-InputReader.subscribe(input => process.stdout.write(CliPrettify.prettify(input)));
+const checkOnly = process.argv.length > 2 || process.argv.find(arg => arg === "--check");
+
+InputReader.subscribe(input =>
+    checkOnly
+        ? CliPrettify.check(input)
+        : process.stdout.write(CliPrettify.prettify(input))
+);

cli/inputReader.ts

@@ -1,6 +1,5 @@
 export class InputReader {
     static subscribe(readDone): void {
-        //TODO: read the "--check" argument
         if (process.stdin.isTTY) {
             readDone(process.argv[2] || "");
         } else {

package.json

@@ -48,7 +48,8 @@
     "compile": "tsc -p ./",
     "pretest": "npm run compile",
     "test": "gulp copy-systemTest-resources && node ./out/test/index.js",
-    "prettify-md": "node ./out/cli/index.js"
+    "prettify-md": "node ./out/cli/index.js",
+    "check-md": "node ./out/cli/index.js --check"
   },
   "devDependencies": {
     "@types/mocha": "^7.0.2",

test/systemTests/cliPrettyfierSystemTests.test.ts

@@ -4,17 +4,41 @@ import * as assert from 'assert';
 import { CliPrettify } from '../../cli/cliPrettify';
 
 fs.readdir(path.resolve(__dirname, "resources/"), function(err, files) {
-    suite("CLI Prettyfier system tests", () => {
+    suite("CLI Prettyfier system tests - prettyfied input files match prepared expected files", () => {
         const distinctTests: string[] = getTestFileNames(files);
-
         for (let fileNameRoot of distinctTests) {
             test(`[${fileNameRoot}]`, () => {
                 const input = fs.readFileSync(pathFor(`${fileNameRoot}-input.md`), "utf8");
                 const expected = fs.readFileSync(pathFor(`${fileNameRoot}-expected.md`), "utf8");
 
                 const actual = CliPrettify.prettify(input);
 
-                assert.equal(actual, expected);
+                assert.strictEqual(actual, expected);
+            });
+        }
+    });
+});
+
+fs.readdir(path.resolve(__dirname, "resources/"), function(err, files) {
+    suite("CLI Prettyfier system tests - check() for non pretty files throws error", () => {
+        const distinctTests: string[] = getTestFileNames(files);
+        for (let fileNameRoot of distinctTests) {
+            test(`[${fileNameRoot}]`, () => {
+                const input = fs.readFileSync(pathFor(`${fileNameRoot}-input.md`), "utf8");
+                assert.throws(() => CliPrettify.check(input));
+            });
+        }
+    });
+});
+
+
+fs.readdir(path.resolve(__dirname, "resources/"), function(err, files) {
+    suite("CLI Prettyfier system tests - check() for pretty files does not throw", () => {
+        const distinctTests: string[] = getTestFileNames(files);
+        for (let fileNameRoot of distinctTests) {
+            test(`[${fileNameRoot}]`, () => {
+                const expected = fs.readFileSync(pathFor(`${fileNameRoot}-expected.md`), "utf8");
+                assert.doesNotThrow(() => CliPrettify.check(expected));
             });
         }
     });