swagger-generator.js

const _ = require('lodash');
const fs = require('fs');
const yaml = require('js-yaml');
const header = {
    swagger: '2.0',
    info: {
        version: '1.0.0',
        title: 'Some Title',
        description: 'Some funny description'
    },
    schemes: ['http', 'https'],
    basePath: '/api'
};

/* object */ function readDocs(dir /* string */) {
    const files = fs.readdirSync(dir);
    const docs = {};

    files.forEach(file => {
        if (! /\.yaml$/.test(file)) {
            /* do nothing */
            return;
        }
        const fullpath = path.join(dir, file)

        const data = yaml.load(fs.readFileSync(fullpath, 'utf-8').toString());
        addGeneratedFields(data);
        _.merge(docs, data);
    });

    return docs;
}

/* void */ function addGeneratedFields(data /* object */) {
    const authParam = { 
      in: 'header',
      name: 'Authorization',
      description: 'Authorization token using bearer schema',
      required: true, type: 'string'
    };
    const pathRequiredParam = (name /* string */) => ({
      in: 'path',
      name: name,
      required: true,
      type: 'string',
      description: 'Path parameter'
    });

    if (! ('paths' in data)) {
        return;
    }

    for (const path in data.paths) {
        for (const method in data.paths[path]) {
            const parameters = data.paths[path][method].parameters || [];

            const pathParams = path.match(/{([\w\s\|]+)}/gi);
            if (pathParams) {
                /* path params exists */
                for (const pathParam of pathParams.reverse()) {
                    const paramName = pathParam.replace('{', '').replace('}', '')
                    parameters.unshift(pathRequiredParam(paramName));
                }
            }

            parameters.unshift(authParam);
            data.paths[path][method].parameters = parameters;
        }
    }
}

module.exports = function GenerateDocs(dir /* string */, outFile /* string */) {
    const stream = fs.createWriteStream(outFile, { encoding: 'utf-8', flags: 'w' });

    stream.once('open', fd => {
        stream.write('# This file is generated\n');
        stream.write(yaml.dump(header));
        stream.write(yaml.dump(readDocs(dir)));
        stream.end();
    });
}