问使用node中的postcss修改css字符串

EN

let style = '' +
  'body {display: flex;} ' +
  'body {background: red;}' +
  '#id5 {color: blue;}' +
  '$id7 {color: green;}' +
  '#id5 {color: yellow;}';

const postcss = require('postcss-js');
const postcsscombine = require('postcss-combine-duplicated-selectors');

let combiner = postcss.sync([ postcsscombine ]);
let newStyle = combiner(style);

console.log(newStyle);

'body {display: flex; background: red;} #id5 {color: yellow} #id7 {color: green;}'

{ '0': 'b',
  '1': 'o',
  '2': 'd',
  '3': 'y',
  '4': ' ',
  '5': '{',
  '6': 'd',
  ...
  '100': 'l',
  '101': 'o',
  '102': 'w',
  '103': ';',
  '104': '}' }