I have a node js application.
All the codes are now in javascript.
But in some part of my app I want to use Typescript Interface or enum options.
How can I use Typescript just for those part of the app?
I don't want to refactor all the project to using Typescript.
You can try Flow https://flow.org
Flow in opposition to TypeScript isn't a superset or language. It's a static type checker for JavaScript. Because it's not a language, it can be smoothly integrated with JavaScript with a single comment annotation.
You can add a single .ts file, and use plain javascript for the rest of them.
https://www.typescriptlang.org/
TypeScript is a typed superset of JavaScript that compiles to plain
JavaScript.
[...] Use existing JavaScript code, incorporate popular JavaScript
libraries, and call TypeScript code from JavaScript.
TypeScript compiles to clean, simple JavaScript code which runs on any
browser, in Node.js, or in any JavaScript engine that supports
ECMAScript 3 (or newer).
Related
Recently I was create react app using vite , it is lightweight , less config and fast then compare with webpack . now my question is , is it required bable configuration in Vite project
No, vite does automatic syntax transforms but it only targets browsers that support es modules (firefox & chrome started supporting it around 2018). If you want to support new js features in older browsers you need to add polyfills though. You can read about the exact behavior and how to support even older browsers here.
I think that question need more information about that topic.
Vite.js uses the built-in JavaScript support of the browser, so you don't need to explicitly configure the JavaScript version in Vite.js itself.
When I said Vite.js uses the built-in JavaScript support of the browser, I meant that Vite.js relies on the JavaScript engine of the browser to interpret and run the JavaScript code in your application. The JavaScript engine is the component of the browser that executes JavaScript code. When you visit a web page that contains JavaScript, the browser runs the JavaScript code using its built-in JavaScript engine. This means that the version of JavaScript that is supported by your application is determined by the version of the JavaScript engine that is built into the browser. In the case of Vite.js, the JavaScript code in your application is not transpiled or otherwise modified before being run by the browser. However, if your application uses modern JavaScript syntax that is not supported by the target browsers, you will need to transpile the code to an older version of the language that is supported. In that case, you can use Babel.
No, it is already setup on the background. However if you'd like to adjust Babel's config you can do it. Read the docs here: https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react/README.md
When I first studied TypeScript, I found that node.js doesn't execute TypeScript, so you need to install a TypeScript compiler that converts your TypeScript code into JavaScript.
I searched until I found ts-node (TypeScript execution and REPL for node.js), but when I read the documentation I found that they do the same (here). Even deno (A modern runtime for JavaScript and TypeScript), is doing the same (here).
So my question is: are there any engines to execute TypeScript code without converting it to JavaScript?
No, TypeScript is not a "standalone" language in that sense. It is and always will be a superset of JavaScript. This is why the TypeScript Compiler is often referred to as a transpiler: it doesn't compile to a lower-level language. After tsc has run its checks it transforms existing source to JavaScript by simply stripping out all the TypeScript constructs.
From the intro of the official TypeScript Handbook:
The goal of TypeScript is to be a static typechecker for JavaScript programs - in other words, a tool that runs before your code runs (static) and ensures that the types of the program are correct (typechecked).
So in order to execute TypeScript, you will always need a JavaScript engine. You could adapt an existing JavaScript engine (or build your own) to understand TypeScript as well, but still it would always first have to be an engine conforming to the ECMAScript specification.
Deno is no different. It has a built-in TypeScript Compiler, which is a copy of the official one. From the TypeScript chapter of the Deno manual.
At a high level, Deno converts TypeScript (as well as TSX and JSX) into JavaScript. It does this via a combination of the TypeScript compiler, which we build into Deno, and a Rust library called swc. When the code has been type checked and transformed, it is stored in a cache, ready for the next run without the need to convert it from its source to JavaScript again.
After transpilation, Deno runs the output JavaScript on Google's V8 Engine, the same engine used in NodeJS and Chrome.
As of now there are no typescript aware V8-like runtime egnines.
It's unlikely we would see one. Sometime in the future TC39 will decide on official JS-With-Types proposal. And then typing and correspond
optimizations would be gradually added to V8 itself.
Though, it unlikely would be compatible with typescript directly, but easily transpilable back and forth.
At the moment there are several R&D AOT compilation (directly to static native binaries) projects for the typescript, or at least for the viable subset of it.
https://github.com/ASDAlexander77/TypeScriptCompiler
Installing TypeScript requires node.js. And I assume that TypeScript uses Node.js to compile the .ts to a .js file.
My question is, does that created .js file require node.js? The ones I've seen so far appear not to. I don't want to load node.js into my html pages if it's not used.
thanks - dave
No, TypeScript just emits regular JavaScript.
If you use the "external modules" feature of the language (import x = require('foo');) you'll need to compile for either CommonJS (node) or AMD (require.js) and have those available, but that's opt-in.
Standard NodeJS app utilising module.exports to make the code modular. We'd like to combine all of those files together into a single file a la RequireJS on the client side (which is what we use there). Does anyone know an easy way to do this server-side without wrapping everything in more module wrappers (e.g. RequireJS) e.g. command-line tool ?
Ta
N
If you want to use node.js modules on the client side without additional wrappers (like RequireJS), you'll want to look into using browserify:
https://github.com/substack/node-browserify
It's a very useful build tool that allows you to use node-style require() statements and native node.js modules on the client side. Or, to quote from the github page itself:
Make node-style require() work in the browser with a server-side build step, as if by magic!
I'm looking for a javascript library that attempts to provide the same simple utilities in both the browser environment AND nodejs (iteration, mapping, maybe control-flow) so that code can more easily be re-used across server and client. I know you can hack out parts of any JS library (YUI, jQuery, ...) and get them to work in both environments, I'm just wondering if it's already been done or standardized.
The closest I've seen is this: https://github.com/kof/sharedjs
But it's incomplete and has some odd stuff. I'm wondering if there is something more polished before I fork and hack.
The underscore library was built to add more functional programming to jquery, things like mapping, and also templating.
Because it doesn't rely on the DOM (it leaves that to jquery) it functions well in node.
The RightJS link library has a server build link that has node.js in mind.
From the download page:
RightJS is also available as a server-side library. In this case it contains only the native JavaScript unit extensions and the Class, Observer, Options units along with all the non-DOM utility functions from the Util module.
Our server-side build follows the CommonJS principles and is ready for use with the node.js framework.
Node's GitHub wiki has a list of CommonJS-compatible modules which will run in Node and browsers.
Some of the other modules on that page may also run in a browser environment. For example, the excellent DateJS works fine in Node. (It is available as a NPM.)
Btw, RightJS is also available on NPM