Streaming multiple svg strings to png in nodejs using promises - node.js

Question

I am trying to convert multiple svg strings to png's so I can render them onto a pdf using PdfMake in nodejs. This works fine for one svg, but when I add multiple svg strings, they get overwritten by the last one. With this example code, it renders two images of png2 (svg2).
const promises = [svg1,svg2].map(str => {
const stream = new Readable();
stream.push(str);
stream.push(null);
return svgPromise(stream);
});
const result = await Promise.all(promises);
const png1 = result[0].content;
const png2 = result[1].content;
function svgPromise(stream) {
return new Promise((resolve, reject) => {
const svg = new Rsvg();
stream.pipe(svg);
svg.on("finish", function() {
const buffer = svg.render({
format: "png",
width: width * 2,
height: height * 2
}).data;
const png = datauri.format(".png", buffer);
resolve(png);
});
});
}
Not sure if this error is related to stream or my promise logic. Any ideas?
Dependencies:
"librsvg": "0.7.0"
"pdfmake": "0.1.35"
"datauri": "1.0.5"

Answer 1

It pays to list all the used modules. Assuming you used datauri, it seems you need to initialize a new instance for every call:
svg.on("finish", function() {
const datauri = new Datauri();
const buffer = svg.render({
format: "png",
width: 16,
height: 16
}).data;
const png = datauri.format(".png", buffer);
resolve(png);
});