build sprite

'use strict';
var gulp = require('gulp');
var imacss = require('gulp-imacss');
var imagemin = require('gulp-imagemin');
var pngcrush = require('imagemin-pngcrush');

gulp.task('imacss', function () {
    gulp.src('app/images/sprites/**/*.svg')
        .pipe(imagemin({
            progressive: true,
            svgoPlugins: [{removeViewBox: false}],
            use: [pngcrush()]
        }))
        .pipe(imacss('_svg.scss', 'svg'))
        .pipe(gulp.dest('app/styles/'));
    gulp.src('app/images/sprites/**/*.png')
        .pipe(imagemin({
                progressive: true,
                svgoPlugins: [{removeViewBox: false}],
                use: [pngcrush()]
        }))
        .pipe(imacss('_png.scss', 'png'))
        .pipe(gulp.dest('app/styles/'));
    gulp.src('app/images/sprites/**/*.jpg')
        .pipe(imagemin({
            progressive: true,
            svgoPlugins: [{removeViewBox: false}],
            use: [pngcrush()]
        }))
        .pipe(imacss('_jpg.scss', 'jpg'))
        .pipe(gulp.dest('app/styles/'));
});

gulp.task('serve', function () {
    gulp.watch(['app/images/sprites/**/*'], ['imacss']);
});