blog/lib/tasks/css.ts

import postcss, { Result } from "postcss";
import config from "../../postcss.config.ts";
import { dest, fromGlob } from "../rx-utils.ts";
import { lastValueFrom, mergeMap } from "rxjs";
import hashPaths from "../hash.ts";
import File from "vinyl";
import { Buffer } from "node:buffer";

export const css = async () => {
    await lastValueFrom(
        fromGlob("src/index.css").pipe(
            mergeMap(
                (file) =>
                    new Promise<File>((resolve) =>
                        postcss(config.plugins)
                            .process(file.contents, { from: file.path })
                            .then((result: Result) => {
                                file.contents = Buffer.from(result.css);
                                file.path = "index.css";

                                resolve(file);
                            })
                    ),
            ),
            hashPaths("css.manifest"),
            mergeMap(dest("dist/_assets")),
        ),
    );
};