standard-markdown/index.js

Test your Markdown files for Standard JavaScript Style™

'use strict'

var standard = require('standard')
var fs = require('fs')
var range = require('lodash.range')
var flatten = require('lodash.flatten')
var async = require('async')
var blockOpener = /^```(js|javascript)$/mg
var blockCloser = /^```$/mg

var standardMarkdown = module.exports = {}

standardMarkdown.lintText = function (text, done) {
  var blocks = extractCodeBlocks(text)
  async.map(blocks, function (block, callback) {
    return standard.lintText(block, callback)
  }, function (err, results) {
    if (err) return done(err)
    results = results.map(function (r) {
      return r.results.map(function (res) {
        return res.messages
      })
    })
    results = flatten(flatten(results))
    return done(null, results)
  })
}

standardMarkdown.lintFiles = function (files, done) {
  async.map(files, function (file, callback) {
    standardMarkdown.lintText(fs.readFileSync(file, 'utf8'), function (err, errors) {
      if (err) return callback(err)
      return callback(null, { file: file, errors: errors })
    })
  }, function (err, results) {
    if (err) return done(err)
    return done(null, results)
  })
}

function extractCodeBlocks (text) {
  var lines = text.split('\n')
  var matches = text.match(blockOpener) || []
  return range(matches.length).map(function (index) {
    return extractCodeBlock(lines, index)
  })
}

// Seek out the nth block of javascript code in the file
function extractCodeBlock (lines, targetIndex) {
  var currentIndex = 0
  var insideBlock = false
  return lines.map(function (line) {
    // standard doesn't like trailing whitespace
    line = line.replace(/\s*$/, '')

    if (line.match(blockOpener)) {
      if (currentIndex === targetIndex) {
        insideBlock = true
        line = '// -' + line
      }
      currentIndex++
    }
    if (line.match(blockCloser)) insideBlock = false
    if (!insideBlock) line = '// -' + line
    return line
  }).join('\n').concat('\n') // standard requires a newline at end of file
}