grunt-autoprefixer to grunt-postcss - node.js

Question

The grunt-autoprefixer said "This project has been deprecated in favour of grunt-postcss." So, I want to change it to grunt-postcss.
My current setting in Gruntfile.js for grunt-autoprefixer
autoprefixer: {
options: {
browsers: ['last 1 version']
},
dist: {
files: [{
expand: true,
cwd: '.tmp/styles/',
src: '{,*/}*.css',
dest: '.tmp/styles/'
}]
}
},
If upgrade to grunt-postcss. How can I write my settings in Gruntfile.js?
I saw the README in grunt-postcss, but I didn't get it. Seems some values cannnot mapping to the new settings for grunt-postcss.

Answer 1

It is done like any other postcss processors. See this for example:
var autoprefixer = require('autoprefixer-core');
grunt.initConfig({
postcss: {
options: {
processors: [
autoprefixer({
browsers: ['> 0.5%', 'last 2 versions']
}).postcss
]
},
dist: {
files: {
'dist/': 'css/*.css'
}
}
}
});

Answer 2

Warning from 2020:
The usage of browsers option in autoprefixer processor has changed.
Now you need to move the browsers option into your package.json file:
Gruntfile.js
...
processors: [
...
// No autoprefixer 'browsers' option
require('autoprefixer')(),
...
]
...
package.json
{
...
// 'browserslist' option at the end of the file just above the last curly brace
'browserslist': [
'last 2 versions',
'> 0.5%'
]
}
See: https://github.com/browserslist/browserslist#browserslist-
(This answer I took from the part of my similar answer here: https://stackoverflow.com/a/64079551/12320578)
An example of working postcss-autoprefixer usage:
Gruntfile.js
module.exports = function (grunt) {
grunt.initConfig({
postcss: {
options: {
processors: [
require('autoprefixer')({grid: 'autoplace'}),
],
map: {
inline: false, // save all sourcemaps as separate files...
annotation: 'assets/css/' // ...to the specified directory
}
},
dist: {
files: {
// Generated file target location and source location
'assets/css/style.min.css': 'assets/css/style.css',
'assets/css/info.min.css': 'assets/css/info.css'
}
// or:
/*files: [
{
expand: true,
src: ['assets/css/*.css', '!**/*.min.css'],
ext: '.min.css',
extDot: 'first'
}
]*/
}
},
watch: {
styles: {
files: ['assets/css/style.css', 'assets/css/info.css'],
// or:
/*files: ['assets/css/*.css', '!assets/css/*.min.css'],*/
tasks: ['postcss']
}
}
});
grunt.loadNpmTasks('grunt-contrib-watch');
grunt.loadNpmTasks('grunt-postcss');
};
package.json
{
... // Other already existing options
"browserslist": [
"last 4 versions",
"> 0.5%"
]
}
See https://gruntjs.com/configuring-tasks#building-the-files-object-dynamically