buffer-apg-js/dev/jsonToLESS.js

JavaScript APG, an ABNF Parser Generator

// Reads a JSON file of color and class names.
// Outputs a LESS file defining variable color and class names.
module.exports = function (inFile, outFile) {
    "use strict";

    function capFirst(str) {
        return str.charAt(0).toUpperCase() + str.slice(1);
    }

    function getFileExtension(filename) {
        return filename.slice(((filename.lastIndexOf(".") - 1) >>> 0) + 2);
    }

    let fs = require("fs");
    try {
        /* validate arguments */
        if (!inFile) {
            throw new Error("missing input JSON file (name.json)");
        }
        if (getFileExtension(inFile) !== "json") {
            throw new Error("input JSON file (" + inFile + ") must have .json extension");
        }
        if (!outFile) {
            throw new Error("missing output LESS file (name.less)");
        }
        if (getFileExtension(outFile) !== "less") {
            throw new Error("output LESS file (" + outFile + ") must have .less extension");
        }

        let json = fs.readFileSync(inFile, "utf8");
        let obj = JSON.parse(json);

        /* generate the LESS file */
        let less = "/* This file automatically generated by jsonToless() and LESS. */\n";
        for (let key in obj.colors) {
            less += "@color" + capFirst(key) + ": " + obj.colors[key] + ";\n";
        }
        for (let key in obj.classes) {
            less += "@class" + capFirst(key) + ": " + obj.classes[key] + ";\n";
        }

        fs.writeFileSync(outFile, less);
    } catch (e) {
        console.log("jsonToLESS.js: EXCEPTION: \n");
        console.log(e.message);
    }
};