.js

'use strict';

const through = require('through2');
const yaml = require('js-yaml');
const ejs = require('ejs');
const gutil = require('gulp-util');

module.exports = (template) => {

  return through.obj(function (file, enc, cb) {
    if (file.isNull()) {
      this.push(file);
      return cb();
    }

    if (file.isStream()) {
      this.emit(
        'error',
        new gutil.PluginError('gulp-ejs', 'Streaming not supported')
      );
    }

    const data = yaml.safeLoad(file.contents.toString());
    file.path = gutil.replaceExtension(file.path, '.html');

    try {
      file.contents = new Buffer(
        ejs.render(template, data)
      );

    } catch (err) {
      this.emit('error', new gutil.PluginError('gulp-ejs', err.toString()));
    }

    this.push(file);
    cb();
  });
};