ReasonJun

object //? Object.assign() // Copies properties from one or more objects to a target object and returns the target object. const target = { a: 1, b: 2 }; const source1 = { b: 3, c: 4 }; const source2 = { c: 5, d: 6 }; const result = Object.assign(target, source1, source2); const result1 = { ...target, ...source1, ...source2, }; console.log(target); // { a: 1, b: 3, c: 5, d: 6 } console.log(resul..

number //? .toFixed() // Returns a number as a character representing a number to the specified decimal notation (number of digits). console.log(num.toFixed(2)); // 3.14 console.log(parseFloat(num.toFixed(2))); // 3.14 => number // .toLocalString() // Returns a number as a character in local language format. const num1 = 100000; console.log(num1.toLocaleString()); // 100,000 => string // Number...

array const fruits = new Array('apple', 'banana', 'cherry'); console.log(fruits); // [ 'apple', 'banana', 'cherry' ] const fruits1 = ['apple', 'banana', 'cherry']; console.log(fruits1); // [ 'apple', 'banana', 'cherry' ] console.log(fruits[0]); // apple // 'from' has the iterable property, so it iterates. array = Array.from('text'); // copy console.log(array); // [ 't', 'e', 'x', 't' ] array = A..

truthy / falsy if (0) { console.log('true'); } if ('0') { console.log('true'); // true } // false // 1) false // 2) 0 // 3) null // 4) undefined // 5) NaN // 6) '' // 7) 0n const fruits = ['apple', 'banana']; if (fruits) { console.log('item here'); // item here } const fruits1 = []; if (fruits1.length) { console.log('item here'); // } object // Object literal { key: value } // new Object() // Ob..

const string1 = 'Hello'; const string2 = 'Hello'; const string3 = `Hello ${string1}`; console.log(string3); // Hello Hello const number = -123; console.log(number + 1); // -122 console.log(number + undefined); // NAN console.log(typeof (number + 1)); // -122 console.log(typeof (number + undefined)); // number const a = 0.1; const b = 0.2; console.log(a + b); // 0.30000000000000004 // Floating Po..

Memory stack : function/order of execution heap: where objects are stored Data type javascript Primitive - immutable : Boolean, String, Number, null, undefined, Symbol Reference - mutable : Object, Array Basically, javascript uses call stack memory space to store references and values for primitive types, but uses a separate memory space called Heap for reference types. In this case, the call st..

ECMAScript (or ES) is a standardized scripting language specification that defines the syntax, semantics, and features of the scripting language used by JavaScript. It is the official name for the language commonly known as JavaScript. ECMAScript provides a standardized foundation for implementing and interpreting JavaScript across different platforms and environments. The ECMAScript specificati..

A JavaScript engine is a computer program or virtual machine that interprets and executes JavaScript code. It is responsible for executing JavaScript programs and running JavaScript code within a web browser or a server-side environment. JavaScript engines are designed to efficiently process JavaScript code by performing various tasks, such as parsing the code, optimizing its execution, and mana..

In CSS, media queries allow you to apply different styles based on specific characteristics of the device or viewport where the webpage is being displayed. Media queries provide a way to create responsive designs that adapt to different screen sizes, resolutions, and other device capabilities. Media queries are introduced using the @media rule and can be used to specify different CSS rules and p..

⇒ Occurs when various elements used in the js file do not exist in the corresponding html file ⇒ It is solved by creating common.js. Also common.css too.