.eleventy.js

module.exports = function(eleventyConfig) {
  eleventyConfig.addWatchTarget("./src/css/");
  eleventyConfig.addWatchTarget("./src/js/");
  eleventyConfig.addPassthroughCopy("./src/static");

  eleventyConfig.addFilter("keys", obj => Object.keys(obj));
  eleventyConfig.addFilter("except", (arr=[]) => {
    return arr.filter(function(value) {
      return value != "all";
    }).sort();
  });

  eleventyConfig.addNunjucksFilter("romanize", function(num) {
    if (isNaN(num)) return NaN;
    var digits = String(+num).split(""),
      key = ["","C","CC","CCC","CD","D","DC","DCC","DCCC","CM",
              "","X","XX","XXX","XL","L","LX","LXX","LXXX","XC",
              "","I","II","III","IV","V","VI","VII","VIII","IX"],
      roman = "",
      i = 3;
    while (i--) {
      roman = (key[+digits.pop() + (i * 10)] || "") + roman;
    }
    return Array(+digits.join("") + 1).join("M") + roman;
  });
  
  return {
    templateFormats: [
      "md",
      "njk"
    ],

    dir: {
      input: "src",
      output: "dist"
    },
    markdownTemplateEngine: "njk"
  }
}