function filterKeyframes(css, unusedRules) {
    const usedAnimations = [];
    css.walkDecls((decl) => {
        if (_.endsWith(decl.prop, 'animation-name')) {
            /* Multiple animations, separated by comma */
            usedAnimations.push(...postcss.list.comma(decl.value));
        } else if (_.endsWith(decl.prop, 'animation')) {
            /* Support multiple animations */
            postcss.list.comma(decl.value).forEach((anim) => {
                /* If declared as animation, name can be anywhere in the string; so we include all the properties */
                usedAnimations.push(...postcss.list.space(anim));
            });
        }
    });
    const usedAnimationsSet = new Set(usedAnimations);
    css.walkAtRules(/keyframes$/, (atRule) => {
        if (!usedAnimationsSet.has(atRule.params)) {
            unusedRules.push(atRule);
            atRule.remove();
        }
    });
}
function filterKeyframes(css, unusedRules) {
    const usedAnimations = [];
    css.walkDecls((decl) => {
        if (_.endsWith(decl.prop, 'animation-name')) {
            
            usedAnimations.push(...postcss.list.comma(decl.value));
        } else if (_.endsWith(decl.prop, 'animation')) {
            
            postcss.list.comma(decl.value).forEach((anim) => {
                
                usedAnimations.push(...postcss.list.space(anim));
            });
        }
    });
    const usedAnimationsSet = new Set(usedAnimations);
    css.walkAtRules(/keyframes$/, (atRule) => {
        if (!usedAnimationsSet.has(atRule.params)) {
            unusedRules.push(atRule);
            atRule.remove();
        }
    });
}
function filterKeyframes ( css , unusedRules ) { const usedAnimations = [ ] ; css . walkDecls ( ( decl ) => { if ( _ . endsWith ( decl . prop , 'animation-name' ) ) { /* Multiple animations, separated by comma */ usedAnimations . push ( ... postcss . list . comma ( decl . value ) ) ; } else if ( _ . endsWith ( decl . prop , 'animation' ) ) { /* Support multiple animations */ postcss . list . comma ( decl . value ) . forEach ( ( anim ) => { /* If declared as animation, name can be anywhere in the string; so we include all the properties */ usedAnimations . push ( ... postcss . list . space ( anim ) ) ; } ) ; } } ) ; const usedAnimationsSet = new Set ( usedAnimations ) ; css . walkAtRules ( / keyframes$ / , ( atRule ) => { if ( ! usedAnimationsSet . has ( atRule . params ) ) { unusedRules . push ( atRule ) ; atRule . remove ( ) ; } } ) ; }
Filter @keyframes that are not used
@param  {Object} css             The postcss.Root node
@param  {Array}  animations
@param  {Array}  unusedRules
@return {Array}
Filter