JS/TS
  • JavaScript Development
  • JS Principles
    • JS Principles
      • Primitive data types
      • typeof operator
      • Scope
      • Hoisting
      • IIFE
      • Closure
      • Anonymous functions in JS
      • Conditional (ternary) operator
        • Coercion vs Conversion
      • Event-driven programming
      • Factory Function
      • JSON.stringify()
      • Strict mode
      • super() keyword
      • What are memory leaks?
      • Micro-tasks within an event loop (Summary)
      • Macro-tasks within an event loop (Summary)
      • null vs undefined
    • Memory Management
    • Advanced function concepts
      • Impure vs Pure Functions
      • Factory functions
  • JavaScript Objects & Arrays
    • Introducing JavaScript objects
      • Build-in objects
        • isNaN()
      • RegExp
        • RegExp.prototype.test()
      • String
        • String.prototype.split()
        • String.prototype.slice()
      • Objects
        • Object.assign()
        • Object.create()
        • Object.defineProperties()
        • Object.defineProperty()
        • Object.entries()
        • Object.freeze()
        • Object.getOwnPropertyNames()
        • Object.getPrototypeOf()
        • Object.isFrozen()
        • Object.isSealed()
        • Map
      • Standard built-in methods to work with Arrays
        • Array.of()
        • Array.prototype.concat()
        • Array.prototype.every()
        • Array.prototype.filter()
        • Array.prototype.find()
        • Array.prototype.findIndex()
        • Array.prototype.forEach()
        • Array.prototype.join()
        • Array.prototype.map()
        • Array.prototype.pop()
        • Array.prototype.shift()
        • Array.prototype.reverse()
        • Array.prototype.some()
        • Array.prototype.sort()
        • Array.prototype.splice()
        • Array.prototype.unshift()
        • Array.prototype.includes()
        • Array.prototype.flatMap()
      • Prototypal inheritance
        • Inheritance with the prototype chain
        • Inheriting "methods"
  • JavaScript Mid
    • JavaScript & ES
      • Arrow Function
      • Anonymous Function
      • Callbacks
      • Promises
      • var, let, and const
      • Fetch API (function)
      • Fetch API
      • Synchronous vs Asynchronous
      • Encapsulation
      • Destructuring assignment
      • call() - apply() - bind()
      • 'This' keyword
      • Functional Programming
  • Browser
    • Event-driven programming
  • TypeScript
    • The TypeScript Handbook
      • Basic Types
      • Interfaces
      • Functions
      • Literal Types
      • Unions and Intersection Types
      • Classes
      • Enums
      • Generics
      • Implements vs extends
  • Hackerrank Practices
    • Practices and examples
  • JS Math
    • Mathematical
      • JavaScript | Math.E() function
      • Math.abs( ) Method
      • Math.ceil( ) function
      • Math floor()
      • Math.imul( ) Function
      • Math log( ) Method
      • Math max()/min() Method
      • Math pow( ) Method
      • Math.sign( ) Function
      • Math sqrt( ) Method
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  1. JS Principles
  2. Advanced function concepts

Factory functions

Factory function introduction

The factory function pattern is similar to constructors, but instead of using new to create an object, factory functions simply set up and return the new object when you call the function. Check out this example:

function createTaxCalculator(tax) {
    function calculateTax(amount) {
        return amount * tax;
    }
    return calculateTax;
}

const calculateVatAmount = createTaxCalculator(0.19);
const calculateIncomeTaxAmount = createTaxCalculator(0.25);

console.log(calculateVatAmount(100));
console.log(calculateVatAmount(200));
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Last updated 4 years ago

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