how can we use import syntax of commonjs as well as ES6 modules in ts file

You can use both require (CommonJS syntax) and import (ES6 syntax) in TypeScript files, depending on your project configuration and preferences.

Using require (CommonJS)

const http = require('http');

• Compatibility: require is part of the CommonJS module system, which is the module format used by Node.js by default. TypeScript fully supports CommonJS modules, so you can use require to import modules like you would in regular JavaScript.

Using import (ES6)

import http from 'http';

• ES6 Modules: TypeScript also supports ECMAScript modules (ES modules) introduced in ES6. This syntax is more modern and provides additional features such as tree-shaking (dead code elimination) and a clearer syntax for named exports.

Mixing require and import

import http from 'http';
const fs = require('fs');

• Compatibility: TypeScript allows you to mix import and require statements in the same file. This can be useful when you're working with libraries or modules that are not yet fully migrated to ES6 modules, or when you prefer to use require for certain modules.

Module Resolution Strategy

• TypeScript uses a module resolution strategy to determine how to locate and load modules based on the syntax used (import or require) and the configuration in your tsconfig.json file.

• When using require, TypeScript generally assumes it's working with CommonJS modules, unless configured otherwise. When using import, it assumes ES6 modules unless otherwise configured.

Best Practices

• Consistency: It's generally a good practice to choose one module syntax (import or require) and stick with it throughout your project for consistency, unless you have specific reasons to mix them.

• Configuration: Ensure your tsconfig.json file reflects your chosen module strategy ("module": "commonjs" or "module": "es6") to avoid unexpected behavior or errors.