Nodejs | Tutorial
- Learn Node.js Tutorial 8
- What is Node.js?
- Features of Node.js
- Install Node.js Linux
- Install Node.js Windows
- Node.js REPL
- Node.js Framework
- Node Package Manager (NPM)
- Node Version Manager (NVM)
- Node.js Modules 3
- Node.js File System 2
- Node.js Debugger 2
- Node.js Error Handling 7
- Node.js Error Object
- Node.js Try Catch
- Error First Callback
- EventEmitter Errors
- Using Express.js Middleware
- Using Promises
- Using Async/Await
- Node Process Manager 2
Node.js REPL (Read Eval Print Loop)
In node.js, REPL is a run-time environment and it is similar to Shell or command prompt in Linux or windows machines. The REPL stands for Read-Eval-Print-Loop and it is very useful when we want to test a simple JavaScript or node.js code snippets.
Suppose, if we install a node.js in our machine, then automatically the REPL runtime environment also get installed because by default the node.js will contain a REPL module and it is also called as "Nodejs Interactive Window".
| Type | Description |
|---|---|
| Read | It reads the input statements provided by user, parse it to JavaScript data structure, and stores it in memory for further operations. |
| Eval | It will evaluate the parsed JavaScript data structure and return the result. |
| Whenever the result is ready, then it will print the result. | |
| Loop | Loops the input command until we press Ctrl + C twice to exit from REPL. |
Node.js REPL Commands
| Command | Description |
|---|---|
| .help | It will display all the available commands in REPL terminal. |
| .break | It will make exit from multiline expression. |
| .clear | It will make exit from multiline expression. |
| CTRL + C | It will terminate the current command. |
| CTRL + C (Twice) | It will terminate / close the node.js REPL terminal. |
| CTRL + D | It will terminate / close the node.js REPL terminal. |
| tab key | It will list all the available commands in REPL. |
| Up/Down Keys | It will show the previous commands applied in REPL. |
| .save filename | It will save the current node.js REPL session to the file. |
| .load filename | It will load the specified file content to current node.js REPL session. |