Generate a QR code
A QR code encodes a short piece of text, usually a URL, as a scannable image. The @libs/qrcode module on JSR generates them with no native dependencies, returning an SVG string, a data array, or terminal output.
import { qrcode } from "jsr:@libs/qrcode";The default output is an SVG string, ready to embed in a page or write to a file. SVG scales to any size without blurring, which suits print and high-resolution screens.
const svg = qrcode("https://deno.com", { output: "svg" });
await Deno.writeTextFile("deno-qr.svg", svg);
console.log(svg.startsWith("<?xml")); // trueThe error-correction level trades data capacity for resilience: a higher level still scans when part of the code is damaged or covered, at the cost of a denser image. Levels are LOW, MEDIUM, QUARTILE, and HIGH.
const robust = qrcode("https://deno.com", {
output: "svg",
ecl: "HIGH",
});
console.log(robust.length > svg.length); // trueWithout an output option you get the raw module matrix: a 2D array of booleans where true is a dark cell. Use it to render the code yourself, for example onto a canvas or into another image format.
const matrix = qrcode("https://deno.com");
console.log(`${matrix.length}x${matrix[0].length} grid`); // 29x29 gridRun this example locally using the Deno CLI:
deno run -W https://docs.deno.com/examples/scripts/generate_qr_code.ts