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#!/usr/bin/env node
// Render a Vega-Lite specification to PNG, using node canvasconst {createWriteStream} = require('fs');const render = require('./render');
render('png', function(canvas, arg) {  const file = arg._[1] || null;  const out = file ? createWriteStream(file) : process.stdout;  const stream = canvas.createPNGStream();  stream.on('data', chunk => { out.write(chunk); });});