index.js

#!/usr/bin/env node
/**
 * This script converts the ORM generated by sequelize auto to a form 
 * accepted by hapi sequelize js
 */
const fs = require("fs");
const readline = require('readline');
const assert = require("assert");
const commander = require('commander');

const program = new commander.Command();
program.version('0.0.1');
program
    .description('This application converts models generated by sequelize auto to models accepted by hapi-sequelizejs')
    .option('-i, --input <inputPath>', 'input path for models generated from sequelize auto.','./models')
    .option('-o, --output <outputPath>','output path for models converted to use with hapi sequelize js.','./convertedModels');
program.parse();
const options = program.opts();
const INPUT_PATH = options.input;
const OUTPUT_PATH = options.output;

(async function () {
    let {modelMap2assoc,fileName2modelName,modelName2FileName} = await readAllModels(`${INPUT_PATH}/init-models.js`);
    for (let [modelName,assoc] of modelMap2assoc.entries()){
        let fileName = modelName2FileName.get(modelName);
        await makeFile(fileName,modelName,modelMap2assoc.get(modelName));
    }
})();

/**
 * @param {string} fileName 
 * This function reads the init file generated by sequelize auto and generates 
 * 3 maps 
 *  modelname -> associations
 *  modelname -> filename
 *  filename -> modelname
 */
async function readAllModels(fileName) {
    const fileStream = fs.createReadStream(fileName);
    const rl = readline.createInterface({
        input: fileStream,
        crlfDelay: Infinity
    });
    let modelMap2assoc = new Map();
    let modelFileNames = [];
    let modelNames = [];
    const assocSet = new Set(["belongsTo","belongsToMany","hasMany","hasOne"]);
    let inFunction = false;
    for await (let line of rl) {
        if (line.includes("function initModels(sequelize)")) {
            inFunction = true;
        }
        if(!inFunction){
            if(line.includes("var") && !line.includes("DataTypes")){
                let startIndex = line.indexOf("/");
                let endIndex = line.indexOf(`"`,startIndex);
                let modelfileName = line.substring(startIndex+1,endIndex);
                modelFileNames.push(modelfileName+".js");
            }
        }
        else{
            if (line.includes("var")){
                index = line.indexOf("var");
                line = line.substring(index);
                let firstWhiteSpace = line.indexOf(" ");
                let secondWhiteSpace = line.indexOf(" ",firstWhiteSpace+1);
                let modelName = line.substring(firstWhiteSpace+1,secondWhiteSpace);
                modelNames.push(modelName);
                modelMap2assoc.set(modelName,[]);
            }else{
                line = line.trim()
                let dotIndex = line.indexOf(".");
                let endIndex = line.indexOf("(");
                let association = line.substring(dotIndex+1,endIndex);
                let modelName = line.substring(0,dotIndex);
                if(assocSet.has(association)){
                    modelMap2assoc.get(modelName).push(line);
                }
            }
        }
    }
    console.log(modelNames);
    console.log(modelFileNames);
    assert.strictEqual(modelNames.length,modelFileNames.length);
    let fileName2modelName = new Map();
    let modelName2FileName = new Map();
    for(let i=0;i<modelNames.length;i++){
        fileName2modelName.set(modelFileNames[i],modelNames[i]);
        modelName2FileName.set(modelNames[i],modelFileNames[i]);
    }
    return {modelMap2assoc,fileName2modelName,modelName2FileName};
}

/**
 * @param {string} fileName 
 * Get sequelize definition without associations from filename
 */
async function getSequelizeDefine(fileName,modelName){
    const fileStream = fs.createReadStream(fileName);
    const rl = readline.createInterface({
        input: fileStream,
        crlfDelay: Infinity
    });
    let start = false;
    let strings = [];
    let stack = []; // stack to find matching parethesis end where sequelize define ends
    loop:
        for await(let line of rl){
            if(line.includes("return")){
                start = true;
                line = line.replace("return",`const ${modelName} =`);
                stack.push("(");
                strings.push(line);
                continue;
            }
            if(start){
                strings.push(line);
                for(let c of line){
                    if(stack.length===0){
                        break loop;
                    }else{
                        if(c==="(" && "("===stack[stack.length-1]){
                            stack.push("(");
                        }else if(c===")" && "("===stack[stack.length-1]){
                            stack.pop();
                        }
                    }
                }
            }
        }
    return strings.join("\n")
}
async function makeFile(fileName,modelName,associations){
    let sqlDefString = await getSequelizeDefine(`${INPUT_PATH}/${fileName}`,modelName);
    let modelSet = new Set();
    let modelsPlate = `  const ${modelName} = model.${modelName};\n`
    modelSet.add(modelsPlate);
    let models = [modelName];
    let associationsPlate = "";
    for (assoc of associations){
        let startIndex = assoc.indexOf("(") + 1;
        let endIndex = assoc.indexOf(",");
        let modelName = assoc.substring(startIndex,endIndex);
        let modelString =  `  const ${modelName} = model.${modelName};\n`;
        if (!modelSet.has(modelString)){
            modelsPlate += modelString;
            modelSet.add(modelString);
        }
        associationsPlate += `  ${assoc}\n`;
    }

    let template = 
`const Sequelize = require('sequelize');
module.exports = (sequelize, DataTypes) => {
${sqlDefString}
  ${modelName}.associate = function(model) {
    initRelations(model);
  }
  return ${modelName};
}
const initRelations = (model) =>{
${modelsPlate}

${associationsPlate}
}
`
    fs.writeFileSync(`${OUTPUT_PATH}/${fileName}`,template)
}