Gulp。 Gulp-如果。如何调用多个插件?

Gulp. Gulp-If. How to call several plug-ins?

css.

几个插件的调用如何实现
gulp.task("useref", function() {
    return gulp.src("src/*.html")
        .pipe(useref())
        .pipe(gulpIf("*.js", uglify()))
        .pipe(gulpIf("*.css", combineMq(), cssnano())) // This does not work
        .pipe(gulp.dest("build"));
});

错误:

$ gulp useref
[20:21:12] Using gulpfile ~\Desktop\Gulp\gulpfile.js
[20:21:12] Starting 'useref'...

events.js:154
      throw er; // Unhandled 'error' event
      ^
 Error: D:\Users\Dmitry\Desktop\Gulp\index.html:1:1: Unknown word
<!DOCTYPE html>
^
<html lang="en">

您可以使用 lazypipe:

var lazypipe = require('lazypipe');

gulp.task("useref", function() {
  var cssPipeline = lazypipe()
    .pipe(cssnano)
    .pipe(combineMq, {
      beautify: false
    });

  return gulp.src("src/*.html")
    .pipe(useref())
    .pipe(gulpIf("*.js", uglify()))
    .pipe(gulpIf("*.css", cssPipeline()))
    .pipe(gulp.dest("build"));
});