PostCSS error: [object Object] is not a PostCSS plugin

问题

The error is coming from the postcss plugin, I think I may have written it incorrectly.

I'm trying to add cssnano and autoprefixer to the postcss plugin.

gulp/node_modules/gulp-postcss/node_modules/postcss/lib/processor.js:143
        throw new Error(i + ' is not a PostCSS plugin');
        ^

Error: [object Object] is not a PostCSS plugin
    at Processor.normalize (/Applications/XAMPP/xamppfiles/htdocs/sites/gulp/node_modules/gulp-postcss/node_modules/postcss/lib/processor.js:143:15)
    at new Processor (/Applications/XAMPP/xamppfiles/htdocs/sites/gulp/node_modules/gulp-postcss/node_modules/postcss/lib/processor.js:51:25)
    at postcss (/Applications/XAMPP/xamppfiles/htdocs/sites/gulp/node_modules/gulp-postcss/node_modules/postcss/lib/postcss.js:73:10)
    at Transform.stream._transform (/Applications/XAMPP/xamppfiles/htdocs/sites/gulp/node_modules/gulp-postcss/index.js:47:5)
    at Transform._read (_stream_transform.js:167:10)
    at Transform._write (_stream_transform.js:155:12)
    at doWrite (_stream_writable.js:300:12)
    at writeOrBuffer (_stream_writable.js:286:5)
    at Transform.Writable.write (_stream_writable.js:214:11)
    at DestroyableTransform.ondata (/Applications/XAMPP/xamppfiles/htdocs/sites/gulp/node_modules/gulp-sass/node_modules/through2/node_modules/readable-stream/lib/_stream_readable.js:531:20)
Mac-a45e60e72dad:gulp JoeKonst$

My code:

// Dependancies
var gulp = require('gulp'),
    browserSync = require('browser-sync'),
    plumber = require('gulp-plumber'),
    autoprefixer = require('gulp-autoprefixer'),
    uglify = require('gulp-uglify'),
    compass = require('gulp-compass'),
    rename = require('gulp-rename'),
    nano = require('cssnano'),
    del = require('del'),
    postcss = require('gulp-postcss'),
    sass = require('gulp-sass');

// Styles
gulp.task('styles', function(){
    gulp.src('sass/main.scss')
    .pipe(sass())
    .pipe(postcss([autoprefixer({browsers: ['last 2 versions']}), nano()]))
    .pipe(gulp.dest('css/'));

    gulp.watch('sass/**/*.scss', ['styles']);
});

// Tasks
gulp.task('default', ['styles']);

回答1:

You are using the gulp-autoprefixer package. That's simply a wrapper around the original autoprefixer package that turns it into a gulp plugin, so you can do .pipe(autoprefixer()).

However postcss expects the original package itself, not the gulp plugin.

So instead of this:

autoprefixer = require('gulp-autoprefixer'),

You need to install the autoprefixer package and do this:

autoprefixer = require('autoprefixer'),

回答2:

@rizkit - I found the fix and it's simple. Just run npm i -d postcss and the problem is solved.

Basically, you need both gulp-postcss and postcss plugins in your dependencies for this to work correctly. I'm assuming the gulp-postcss plugin will need to update the postcss package reference in the project to fix it properly, so we only need to include gulp-postcss in the future.

回答3:

If you use autoprefixer 10 you might stumble upon that problem again, there is a github issue related to that with some links and explanations: https://github.com/postcss/autoprefixer/issues/1358

tl;dr:

for postcss-cli and gulp-postcss you have to wait for an update, for PostStylus you might never get an update.
or add postcss as a devDependency

回答4:

Tailwindcss & React issue

For anyone facing the above issue while setting up a react project with tailwindcss, running npm i postcss -D worked for me.

来源：https://stackoverflow.com/questions/40090111/postcss-error-object-object-is-not-a-postcss-plugin

标签

gulp

postcss