ultraviolet/rewrite/css.js

import { parse, walk, generate } from "css-tree";
import EventEmitter from "./events.js";
import parsel from "./parsel.js";

class CSS extends EventEmitter {
    constructor(ctx) {
        super();
        this.ctx = ctx;
        this.meta = ctx.meta;
        this.parsel = parsel;
        this.parse = parse;
        this.walk = walk;
        this.generate = generate;
    };
    rewrite(str, options) {
        return this.recast(str, options, 'rewrite');
    };
    source(str, options) {
        return this.recast(str, options, 'source');
    };
    recast(str, options, type) {
        if (!str) return str;
        str = new String(str).toString();
        try {
            const ast = this.parse(str, { ...options, parseCustomProperty: true });
            this.walk(ast, node => {
                this.emit(node.type, node, options, type);
            });
            return this.generate(ast);
        } catch(e) {
            return str;
        };
    };
};

export default CSS;