Change working directory before linting

Otherwise, ESLint runs from the root directory which results in slightly different behavior than running standard on the command line. For example, if the project directory is within a hidden directory (e.g. /home/jane/.secret/project), ESLint ignores all files. Fixes #222.

We cannot use standard’s cwd option here because standard-engine does not pass the cwd through to ESLint. See standard/standard-engine#189.

lib/linter-js-standard.js

@@ -1,4 +1,5 @@
 // Dependencies
+var path = require('path')
 var linter = require('./utils/linter')
 var allowUnsafeNewFunction = require('loophole').allowUnsafeNewFunction
 var markdownSplitter = require('./utils/markdown-splitter')
@@ -15,7 +16,14 @@ function generateLintPromise (textEditor, filePath, fileContent, settings, lineS
         lineStart: lineStart || 0
       })
 
+      var workingDirectory = path.dirname(filePath)
+      var previousWorkingDirectory = process.cwd()
+
+      process.chdir(workingDirectory)
+
       settings.style.lintText(fileContent, settings.opts, (err, results) => {
+        process.chdir(previousWorkingDirectory)
+
         if (err) {
           return reject(err)
         }