leadingUnderscore.js

import postcss from 'postcss';
import plugin from '../plugin';
import {IE_6} from '../dictionary/browsers';
import {PROPERTY} from '../dictionary/identifiers';
import {DECL} from '../dictionary/postcss';

export default plugin([IE_6], [DECL], function (decl) {
    const {before} = decl.raws;

    if (before && ~before.indexOf('_')) {
        this.push(decl, {
            identifier: PROPERTY,
            hack: `${before.trim()}${decl.prop}`,
        });
    }

    if (decl.prop[0] === '-' && decl.prop[1] !== '-' && postcss.vendor.prefix(decl.prop) === '') {
        this.push(decl, {
            identifier: PROPERTY,
            hack: decl.prop,
        });
    }
});