node_modules/csso/lib/replace/Atrule.js

var resolveKeyword = require('css-tree').keyword;
var compressKeyframes = require('./atrule/keyframes');

module.exports = function(node) {
    // compress @keyframe selectors
    if (resolveKeyword(node.name).basename === 'keyframes') {
        compressKeyframes(node);
    }
};