ReasonJun

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..