Add -s/--stdin option to read from STDIN instead of file|directory|gl…

…ob (fixes #32).

README.md

@@ -21,6 +21,7 @@ $ markdownlint --help
 
     -h, --help                          output usage information
     -V, --version                       output the version number
+    -s, --stdin                         read from STDIN (no files)
     -c, --config [configFile]           configuration file
     -i, --ignore [file|directory|glob]  files to ignore/exclude
 ```

markdownlint.js

@@ -5,6 +5,7 @@
 var fs = require('fs');
 var path = require('path');
 var program = require('commander');
+var getStdin = require('get-stdin');
 var differenceWith = require('lodash.differencewith');
 var flatten = require('lodash.flatten');
 var extend = require('deep-extend');
@@ -62,15 +63,6 @@ function prepareFileList(files) {
   });
 }
 
-function lint(lintFiles, config) {
-  var lintOptions = {
-    resultVersion: 2,
-    files: lintFiles,
-    config: config
-  };
-  return markdownlint.sync(lintOptions);
-}
-
 function printResult(lintResult) {
   var results = flatten(Object.keys(lintResult).map(function (file) {
     return lintResult[file].map(function (result) {
@@ -111,6 +103,7 @@ program
   .version(pkg.version)
   .description(pkg.description)
   .usage('[options] <files|directories|globs>')
+  .option('-s, --stdin', 'read from STDIN (no files)')
   .option('-c, --config [configFile]', 'configuration file')
   .option('-i, --ignore [file|directory|glob]', 'files to ignore/exclude', concatArray, []);
 
@@ -124,10 +117,23 @@ var diff = differenceWith(files, ignores, function (a, b) {
   return paths.original;
 });
 
-if (files.length > 0) {
+function lintAndPrint(stdin, files) {
   var config = readConfiguration(program);
-  var lintResult = lint(diff, config);
+  var lintOptions = {
+    config: config,
+    files: files || [],
+    strings: {
+      stdin: stdin || ''
+    }
+  };
+  var lintResult = markdownlint.sync(lintOptions);
   printResult(lintResult);
+}
+
+if ((files.length > 0) && !program.stdin) {
+  lintAndPrint(null, diff);
+} else if ((files.length === 0) && program.stdin) {
+  getStdin().then(lintAndPrint);
 } else {
   program.help();
 }

package.json

@@ -38,6 +38,7 @@
   "dependencies": {
     "commander": "~2.9.0",
     "deep-extend": "~0.4.1",
+    "get-stdin": "~5.0.1",
     "glob": "~7.0.3",
     "lodash.differencewith": "~4.5.0",
     "lodash.flatten": "~4.4.0",

test/test.js

@@ -4,7 +4,7 @@ import path from 'path';
 import test from 'ava';
 import execa from 'execa';
 
-const errorPattern = /\.(md|markdown): \d+: MD\d{3}/gm;
+const errorPattern = /(\.md|\.markdown|stdin): \d+: MD\d{3}/gm;
 
 test('--version option', async t => {
   const result = await execa('../markdownlint.js', ['--version']);
@@ -20,6 +20,18 @@ test('--help option', async t => {
   t.true(result.stderr === '');
 });
 
+test('no files shows help', async t => {
+  const result = await execa('../markdownlint.js', []);
+  t.true(result.stdout.indexOf('--help') >= 0);
+  t.true(result.stderr === '');
+});
+
+test('files and --stdin shows help', async t => {
+  const result = await execa('../markdownlint.js', ['--stdin', 'correct.md']);
+  t.true(result.stdout.indexOf('--help') >= 0);
+  t.true(result.stderr === '');
+});
+
 test('linting of correct Markdown file yields no output', async t => {
   const result = await execa('../markdownlint.js',
     ['--config', 'test-config.json', 'correct.md']);
@@ -209,3 +221,36 @@ test('glob linting does not try to lint directories as files', async t => {
     t.true(err.stderr.match(errorPattern).length > 0);
   }
 });
+
+test('--stdin with empty input has no output', async t => {
+  var input = '';
+  const result = await execa('../markdownlint.js', ['--stdin'], {input: input});
+  t.true(result.stdout === '');
+  t.true(result.stderr === '');
+});
+
+test('--stdin with valid input has no output', async t => {
+  var input = [
+    '# Heading',
+    '',
+    'Text'
+  ].join('\n');
+  const result = await execa('../markdownlint.js', ['--stdin'], {input: input});
+  t.true(result.stdout === '');
+  t.true(result.stderr === '');
+});
+
+test('--stdin with invalid input reports violations', async t => {
+  var input = [
+    'Heading',
+    '',
+    'Text '
+  ].join('\n');
+  try {
+    await execa('../markdownlint.js', ['--stdin'], {input: input});
+    t.fail();
+  } catch (err) {
+    t.true(err.stdout === '');
+    t.true(err.stderr.match(errorPattern).length === 2);
+  }
+});