fs.js

'use strict';

var fs = require('fs');
var path = require('path');
var utils = require('./utils');

/**
 * Expose `helpers`
 */

var helpers = module.exports;

/**
 * Converts bytes into a nice representation with unit.
 *
 * **Examples:**
 *
 *   - `13661855 => 13.7 MB`
 *   - `825399 => 825 KB`
 *   - `1396 => 1 KB`
 *
 * @param {String} `value`
 * @return {String}
 * @api public
 */

helpers.fileSize = function(num) {
  var bytes = parseInt(num, 10);

  if (!utils.isNumber(bytes)) {
    console.error('helper {{fileSize}} cannot parse: "' + num + '"');
    return num.toString(); // Graceful degradation
  }

  // KB is technically a Kilobit, but it seems more readable.
  var metric = ['byte', 'bytes', 'KB', 'MB', 'GB'];

  var res;
  if (bytes === 0) {
    return '0 bytes';
  } else {
    // Base 1000 (rather than 1024) matches Mac OS X
    res = Math.floor(Math.log(bytes) / Math.log(1000));

    // No decimals for anything smaller than 1 MB
    num = (bytes / Math.pow(1000, Math.floor(res))).toFixed(res < 2 ? 0 : 1);

    if (bytes === 1) {
      res = -1; // special case: 1 byte (singular)
    }
  }
  return num + ' ' + metric[res + 1];
};

/**
 * Read a file from the file system. This is useful in composing
 * "include"-style helpers using sub-expressions.
 *
 * ```js
 * {{read "a/b/c.js"}}
 * {{someHelper (read "a/b/c.md")}}
 * ```
 * @param {String} `filepath`
 * @return {String}
 * @api public
 */

helpers.read = function(filepath) {
  return fs.readFileSync(filepath, 'utf8');
};

/**
 * Return an array of files from the given
 * directory.
 *
 * @param {String} `directory`
 * @return {Array}
 * @api public
 */

helpers.readdir = function(dir, filter) {
  var files = fs.readdirSync(dir);
  files = files.map(function(fp) {
    return path.join(dir, fp);
  });
  if (utils.isOptions(filter)) {
    return files;
  }
  if (typeof filter === 'function') {
    return filter(files);
  }
  if (utils.isRegex(filter)) {
    var re = utils.toRegex(filter);
    return files.filter(function(fp) {
      return re.test(fp);
    });
  }
  if (utils.isGlob(filter)) {
    var isMatch = utils.mm.matcher(filter);
    return files.filter(function(fp) {
      return isMatch(fp);
    });
  }
  if (['isFile', 'isDirectory'].indexOf(filter) !== -1) {
    return files.filter(function(fp) {
      var stat = fs.statSync(fp);
      return stat[filter]();
    });
  }
  return files;
};