You must install Node.js on your computer before you can begin. Check this to install Node.js in your windows.
Once Node.js is installed, you may begin creating your first Node.js application. Here is a straightforward illustration of how to build a web server using the HTTP module:
Example: This is the basic example of NodeJs:
Things to learn before Node.js:
- Identifiers: Identifiers are used to name variables, functions, and other elements in the code. They can contain letters, digits, underscores (_), and dollar signs ($), and must begin with a letter, an underscore, or a dollar sign.
- Literals: These fixed values are spelled out in the code as literals. Examples include booleans, strings, and integers (for instance, 42), as well as (e.g., true).
- Variables: They are referred to be designated storage areas for values. A variable’s value might change while the program is running.
- Operators: These unique symbols carry out operations on a single or a collection of values. Examples include comparison operators like, >, ==, and!= as well as arithmetic operators like +, -, *, and /.
- Function calls: These expressions are ones that call functions. The expression’s value is determined by using the return value from the function after it has been called with the specified inputs.
- Array and object literals: These expressions produce new objects or arrays.
- String: A string of characters, such as words or sentences, is represented by this data type. Strings require quotation marks (‘ or “).
- Boolean: This data type shows whether a value is true or false. It is frequently used to check for specific criteria in conditional expressions.
- Null: This data type represents the absence of a value or a null reference. It is an intentional assignment of nothingness.
- Undefined: This data type represents the absence of a value or an uninitialized variable. It is different from null in that it is not an intentional assignment of nothingness.
- Object: This data type represents a collection of key-value pairs. It is used to store complex data structures, such as arrays and dictionaries.
The way the function is called, not the way it is defined, determines the value of this. This implies that depending on the context in which the function is invoked, the value of this may change.
- for: A code block is repeated using this loop a certain number of times.
- for-in: This loop is used to traverse over an object’s properties.
- for-of: The values of an iterable object are iterated through in this loop (such as an array or a string).
- while: This loop iterates around a block of code until a certain condition is met.
- do-while: This loop is similar to a while loop, it always executes the code block at least once, and it checks the condition thereafter.
- Global scope: Variables are said to be in the global scope if they are defined outside of any function. Anywhere in the program can access them.
- Local Scope: Variables defined inside of a function are referred to as being in the local scope. Only the function in which they were declared can access them.
You may add the phrase “use strict” at the start of a script, function, or block of code to activate the strict mode.
The following are some of the adjustments that the stringent mode makes:
- prevents the usage of variables that are not declared.
- prevents the unintentional creation of global variables.
- prevents the deletion of variables, functions, or arguments that are regarded as non-configurable.
- prevents the null or undefined value from being changed to another one.
- prevents using a parameter with the same name as a variable or function specified in the same function.
ECMAScript 2015 (ES6) and beyond:
- Defining function expressions succinctly is possible using arrow functions.
- Classes: These offer a syntax for designing object-oriented programming and for generating objects.
- With the use of template literals, you may include expressions into strings.
- These new methods for declaring variables with block scope are let and const.
- Code may be organized and reused using modules.
The exponentiation operator (**) and the Array.prototype.includes() function were added in ECMAScript 2016 (ES7).
ECMAScript 2017 (ES8): Introduced the Object.values() and Object.entries() methods, and the async and await keywords for working with asynchronous code.
ECMAScript 2018 (ES9): Introduced the async iteration and rest/spread properties syntax.
ECMAScript 2019 (ES10): Introduced the Array.prototype.flat() and Array.prototype.flatMap() methods, and the trimStart() and trimEnd() methods for strings.
Modules: Node.js uses a modular design, which means that you can organize your code into smaller, reusable chunks called modules. Understanding how to create, import and export modules is crucial for building scalable and maintainable Node.js applications.
HTTP: Node.js includes a built-in HTTP module that allows you to create servers and make HTTP requests. Understanding how to use this module is essential for building web servers and interacting with APIs.
Streams: Node.js includes a built-in stream module that allows you to work with streaming data. Understanding how to read from and write to streams is useful for working with large amounts of data or building efficient data pipelines.
Node.js includes a built-in stream module that allows you to work with streaming data. Understanding how to read from and write to streams is useful for working with large amounts of data or building efficient data pipelines.
File system: Node.js includes a built-in file system module that allows you to read from and write to the file system. Understanding how to use this module is useful for reading and writing data to the file system, as well as interacting with the file system in other ways.
Debugging: Debugging Node.js applications can be challenging due to the asynchronous nature of the language. Familiarity with tools such as the Node.js debugger and console.log will be helpful in troubleshooting and identifying issues in your code.
Node.js is built on an event-driven architecture, which means that it is designed to handle asynchronous operations. This means that you will need to be familiar with concepts such as callbacks, promises, and async/await in order to write efficient and effective Node.js code.
Callbacks: These are functions that are passed as arguments to another function, and they are called when the task is complete.
Promises: These are objects that represent the eventual completion (or failure) of an asynchronous operation. They have a then() method that is called when the operation is complete and an optional catch() method that is called if the operation fails.
Async/await: These are keywords that can be used to write asynchronous code that looks synchronous. They are used in combination with async functions and Promises.
There are two types of timers: setTimeout and setInterval.
- setTimeout: This function executes a piece of code after a specified number of milliseconds have passed.
- setInterval: This function executes a piece of code repeatedly at a specified interval (in milliseconds).
The event loop works by continuously checking a queue of pending events and executing the code associated with those events. When there are no more pending events, the event loop waits for new events to be added to the queue.
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