export png from artboards and slices in sketch

sketch2png.js

var gulp = require('gulp');
var sketch = require('gulp-sketch');
var argv = require('yargs').argv;
var del = require('del');
var runSequence = require('run-sequence');

var outputDir = './output/';

if (!argv && argv.path) {
    throw new Error('path argument missing');
}

var inputGlob = argv.path;

gulp.task('clean', function () {
    del([outputDir + '/**/*']);
});

gulp.task('exportSlices', function () {
    return gulp.src(inputGlob)
        .pipe(sketch({
            export: 'slices',
            formats: 'png'
        }))
        .pipe(gulp.dest(outputDir));
});

gulp.task('exportArtboards', function () {
    return gulp.src(inputGlob)
        .pipe(sketch({
            export: 'artboards',
            formats: 'png'
        }))
        .pipe(gulp.dest(outputDir));
});

gulp.task('default', ['export'], function () {
    gulp.watch(inputGlob, ['export']);
});

gulp.task('export', function (cb) {
    runSequence(['clean', 'exportArtboards', 'exportSlices'], cb);
});