const gulp = require('gulp');
const frontMatter = require('gulp-front-matter');

gulp.task('blog-posts', () => {
  return gulp.src('./posts/*.md')
    .pipe(frontMatter({ // optional configuration
      property: 'frontMatter', // property added to file object
                               // also works with deep property selectors
                               // e.g., 'data.foo.bar'
      remove: true // should we remove front-matter header?
    }))
    .pipe(…) // you may want to take a look at gulp-marked at this point
});