Auto test generate

var chokidar = require('chokidar');
var fs = require('fs')
var path = require('path')
var testFileExtension = 'spec.js'
var ignorefile = [/[\/\\]\./, 'package.json', 'node_modules', 'watcher.js'];
/**
 * @getTemplate A function to get Tempate content for new test file
 * @filename It just take on argument that is file
 * @returns : string
 **/
function getModuleTemplate(filename) {

    return `var assert = require('chai').assert;

describe('${filename} modules', function() {

});`

}
/**
 * @param { String } functionName name of the function for Tempate
 * @returns { String } Tempate String
 **/
function getTestTemplate(filename) {

    return `

    describe('${filename} function', function() {

    });`

}
/**
 * @createTestFile A function that create the test file with Tempate string
 * @filepath : first argument for file path
 * @callback : It's callback that call after file created 
 **/
function createTestFile(filepath = '', callback) {
    let basename = path.basename(filepath, '.js')
    filepath = getTestFilePath(filepath)
    if (!fs.existsSync(filepath)) {
        fs.writeFile(filepath, getModuleTemplate(basename), 'utf8', function (err) {
            if (err) {
                callback(err, null)
            }
            callback(null, filepath)
        });
    }
}
/** 
 *  @function : isTestFile function for check filepath is test file path or a simple js file path
 *  @filepath : Simple file path
 *  @returns : boolean
 **/
function isTestFile(filepath = '') {
    let index = path.basename(filepath).indexOf(testFileExtension) !== -1 ? true : false;
    return index
}
/** 
 *  @function : isTestFile function for check filepath is js file path or not
 *  @filepath : Simple file path
 *  @returns : boolean
 **/
function isJsFile(filepath = '') {
    let extension = path.extname(filepath)
    return ('.js' === extension)
}
/** 
 *  @function : isAbsolutePath function for check filepath is absolute file path or not
 *  @filepath : Simple file path
 *  @returns : boolean
 **/
function isAbsolutePath(filepath = '') {
    return path.isAbsolute(filepath)
}

/** 
 *  @function : getWatcher function that returns object of file and directory watcher
 *  @ignorefile : array => Array of file and folder name that we wish to ignored from watch
 *  @returns : object
 **/
function getWatcher(ignorefile) {
    return chokidar.watch('.', {
        ignored: ignorefile,
        persistent: true
    });
}
/**
 * @param {String} filepath is name of the file
 * @returns {String} Name of the test file name
 **/
function getTestFilePath(filepath = '') {
    let dirname = path.dirname(filepath) !== '.' ? '/' + path.dirname(filepath) + '/' : '/'
    let basename = path.basename(filepath, '.js')
    filepath = __dirname + dirname + basename + testFileExtension
    return filepath
}
/**
 * @param {buffer} Buffer from where need to get function name List
 * @returns {Array} Array of function names
 **/
function getFunNames(fileBuffer) {
    var bufferLength = fileBuffer.length
    var funNameArray = []
    var ifFunction = ''
    var functionName = ''
    var word = 'function'
    for (let i = 0; i < bufferLength; i++) {

        if (word.indexOf(ifFunction) == -1 || fileBuffer[i] == 10) {
            ifFunction = ''
        }
        else if (word == ifFunction) {
            if (fileBuffer[i] != 8 && fileBuffer[i] != 9 && fileBuffer[i] != 10 && fileBuffer[i] != 11 && fileBuffer[i] != 32 && fileBuffer[i] != 40) {
                functionName = functionName + String.fromCharCode(fileBuffer[i])
            }
            else if (fileBuffer[i] == 40) {
                funNameArray.push(functionName);
                functionName = ''
                ifFunction = ''
            }
        }
        else {
            ifFunction = ifFunction + String.fromCharCode(fileBuffer[i])
        }
    }
    return funNameArray
}
/**
 * function Descption : Just insert the test Tempate for function
 * @param { String } testFilePath File path to which we need to insert Tempate
 * @param { String } functionName Name of  the function for Tempate
**/
function insertTestTemplate(testFilePath = '', functionName = '') {
    testFilePath = getTestFilePath(testFilePath)
    let fileContent = fs.readFileSync(testFilePath, 'utf8')
    let index = fileContent.indexOf('{');
    let firstpart = fileContent.slice(0, index + 1)
    let lastpart = fileContent.slice(index + 1)
    let newContent = firstpart + getTestTemplate(functionName) + lastpart
    fs.writeFileSync(testFilePath, newContent, 'utf-8');
}
/**
 * function Descption : Just insert the test Tempate for function
 * @param { String } testFilePath File path to which we need to insert Tempate
 * @param { String } content to be written to the file
**/
function insertTestCases(testFilePath = '', content) {
    testFilePath = getTestFilePath(testFilePath)
    let fileContent = fs.readFileSync(testFilePath, 'utf8')
    let index = fileContent.indexOf('{');
    let firstpart = fileContent.slice(0, index + 1)
    let lastpart = fileContent.slice(index + 1)
    let newContent = firstpart + content + lastpart
    fs.writeFileSync(testFilePath, newContent, 'utf-8');
}
/**
 * @param { String } testFilePath File path to which we need to insert Tempate
 * @param { String } functionName Name of  the function for Tempate
 * @returns { boolean } true if exist false if not
**/
function isTestExistFor(testFilePath = '', functionName = '') {
    testFilePath = getTestFilePath(testFilePath)
    let fileContent = fs.readFileSync(testFilePath, 'utf8')
    let templateToSearch = `describe('${functionName} function', function() {`
    let index = fileContent.indexOf(templateToSearch) == -1 ? false : true;
    return index
}
/**
 * @call : call getWatcher function
 **/
watcher = getWatcher(ignorefile);
/** 
 *  Add Lister to the wath object
 **/
watcher
    .on('add', path => {
        let created;
        if (isJsFile(path) && !isTestFile(path)) {
            createTestFile(path, (err, path) => {
                if (err) {
                    console.log("sorry we cought an error" + err)
                }
                console.log("File :" + path + " created")
            })
        }
    })
    .on('change', (path, stats) => {
        if (isJsFile(path) && !isTestFile(path)) {
            var funcNameList = [];
            var myReadStream = fs.createReadStream(path)
            myReadStream.on('data', fileBuffer => {
                var names = getFunNames(fileBuffer)
                names.forEach(name => {
                    if (funcNameList.indexOf(name) == -1)
                        funcNameList.push(name)
                })
            })
            myReadStream.on('close', () => {

                funcNameList.forEach(names => {
                    if (!isTestExistFor(path, names))
                        insertTestTemplate(path, names)
                })
            })
        }
    })
    .on('unlink', path => {
        console.log(`File ${path} has been removed`)
    });