How to dynamically create and write content inside files and folders with nodejs if making a starter kit generator

I want to create a Project Starter Kit Generator for a framework just like Angular CLI with node.js.

Following are the features that will be needed assuming the command would be kit-cli:

• kit-cli init or kit-cli am/as : will ask few questions and based on that it will create all the files and folders to get started.

• kit-cli add option : will create and add some codes into existing files and will run some system based commands if required.

I have following approach in my mind:

• Putting my content into JSON files.

• Based on User's choices, read content from JSON file and create folders and files.

• No idea about how I will add/remove codes from a existing file.

Questions:

• How should I store and create the folder/file structure assuming that the folder structure will vary based on user's choices.

• How should I edit/add/remove code from an existing file.

You can use node file system for that or a pure shell script. With node:

const fs = require("fs");

fs.writeFile(filePath, fileData, (err,res) => {
    if(err) console.log(err);
    console.log(res);
});

To write files in node:

fs.readFile('./file3.json', (err,res) => {
    let file = res;
    console.log(res.toString('utf-8'));
});

You can wrap the fs.writeFile so you can reuse it with all files you need, like this:

createFile('./file1.json', '{"pro1": "value1"', "prop2": "value2"}');
createFile('./file2.json', '{"pro3": "value3"', "prop4": "value4"}');
createFile('./file3.json', '{"pro5": "value5"', "prop6": "value6"}');

function createFile(path, data) {
    fs.writeFile(path, data, (err,res) => {
        if(err) console.log(err);
        console.log(res);
    });
}

This is how you can read a js file:

fs.readFile('./file.js', (err,res) => {
    let file = res.toString('utf-8');
    console.log(file);
    let lines = file.split('\n');
    for(var i = 0; i < lines.length; i++) {
        console.log(lines[i]);
    }
});

This is how you would add modules to it:

let modules = ['const def = require("def");', 'const xyz = require("xyz");'];

fs.readFile('./abc.js', (err,res) => {
    let file = res.toString('utf-8');
    let lines = file.split('\n');
    for(var i = 0; i < lines.length; i++) {
        if(i==0) {
            let mod = '';
            for(var j = 0; j < modules.length; j++) {
               mod += modules[j] + "\n"; 
            }
            lines[i] = mod + lines[i];
        }
    }
    let newFile = lines.join('\n');
    createFile('./abc.js', newFile);
});

We are checking if we are at the first line of the file, so we know thats where we place the modules imports.

You can define all your modules in the array and add it to the first line before the first module, thats why:

lines[i] = mod + lines[i];

Then we take all lines and add back a new line between them to save our file.

let newFile = lines.join('\n');
createFile('./abc.js', newFile);

This is how you can check if you are at the end of a method declaration:

if(lines[i].includes('});')) {
        lines[i] = '\tconsole.log("xyz added");\n\n' + lines[i];
}

To make sure you add to the right method instead of all of them:

if(lines[i].includes('});') && lines[i].includes('abc')) {
    lines[i] = '\tconsole.log("xyz added");\n\n' + lines[i];
}

And add the comment in your method declaration:

abc.method(function () { 
  console.log("abc called");
}); // end of abc