Added basic command-line flags for width and output file name

poptimal.js

@@ -2,6 +2,8 @@ import {  Resvg } from "@resvg/resvg-js";
 import { promises } from "fs";
 import { JSDOM } from "jsdom";
 import * as d3 from "d3";
+import yargs from "yargs/yargs";
+import { hideBin } from "yargs/helpers";
 
 import random from "random";
 
@@ -86,19 +88,24 @@ function poptimal_svg() {
 }
 
 async function main() {
-	const svg = poptimal_svg();
+	const argv = yargs(hideBin(process.argv))
+		.usage("Usage: -w WIDTH -o OUTPUT_PNG")
+		.default('w', 1200)
+		.default('o', 'poptimal.png').argv;
+
+	const svg = poptimal_svg(argv.w);
 	const opts = {
     	background: 'rgba(255, 255, 255, 1.0)',
     	fitTo: {
       		mode: 'width',
-      		value: 1200,
+      		value: argv.w,
     	},
     };
   	const resvg = new Resvg(svg, opts)
  	const pngData = resvg.render()
   	const pngBuffer = pngData.asPng()
 
-  	await promises.writeFile('test.png', pngBuffer);
+  	await promises.writeFile(argv.o, pngBuffer);
 }