If you are new here make sure to check my last 2 parts regarding functional programming on The Codest<\/a> blog about:<\/p>\n\n\n\n It has no complex logic. Its main task is to wrap the context and perform the functions it receives from the outside on them. Each time the value changes, a new container instance is repackaged and returned. When calling the map<\/b> method, which takes a specific action, it returns a new container instance with the value returned by the passed function, while maintaining the non-modifiable principle.<\/p>\n\n\n\n map<\/b> – useful when you want to change the state of a value in a container but don’t want to return it yet.<\/p>\n\n\n\n chain<\/b> – used if you want to pass a value to a function without modifying the container state. Usually at the end of map<\/b> calls.<\/p>\n\n\n\n of<\/b> – return current value<\/p>\n\n\n\n Sometimes, in addition to the functions that trigger the new state of the value, you need additional logic hidden in the container. This is where monad comes in handy, as it is an extension of functor<\/b>. It can, for example, decide what should happen when the value has a certain value or what path the next actions are to take.<\/p>\n\n\n\n Monad maybe solves the problem of values that return not true. When this happens, subsequent map<\/b> calls are ignored, but it allows you to return an alternative by calling the getOr<\/b> method. It allows you to avoid the use of if \/ else operators, which are popular in imperative<\/b> programming. This monad consists of three containers:<\/p>\n\n\n\n Nothing<\/b> – runs when a value that is not true falls into the container or filter<\/strong> method returns false. It is used to simulate the execution of a function. This means that this container receives the function but does not execute it.<\/p>\n\n\n\n Just<\/b> – this is the main container that performs all the functions, but if the value changes to a false value or filter<\/b> method returns false, it will pass it to the Nothing<\/b> container.<\/p>\n\n\n\n\n
Functor<\/h2>\n\n\n\n
Declaration<\/h3>\n\n\n\n
const Functor = value => ({\n map: fn => Functor(fn(value)),\n chain: fn => fn(value),\n of: () => value\n });<\/code><\/code><\/pre>\n\n\n\nImperative example<\/h3>\n\n\n\n
const randomInt = (max) => Math.floor(Math.random() * (max + 1))\n\nconst randomNumber = randomInt(200) \/\/ returns number between 0 and 200\n\ndecrease(randomNumber) \/\/ returns (number between 0 and 200) - 1<\/code><\/pre>\n\n\n\nDeclarative example<\/h3>\n\n\n\n
const randomIntWrapper = (max) =>\nFunctor(max)\n.map(increase) \/\/ max + 1\n.map(multiplyBy(Math.random())) \/\/ Math.random() * (max + 1)\n.map(Math.floor) \/\/ Math.floor(Math.random() * (max + 1))\n\nconst randomNumber = randomIntWrapper(200)\n\nrandomNumber.of() \/\/ returns number between 0 and 200\nrandomNumber.chain(decrease) \/\/ returns (number between 0 and 200) - 1<\/code><\/pre>\n\n\n\nMonad<\/h2>\n\n\n\n
Monad Maybe<\/h2>\n\n\n\n
![\"table](\"\/app\/uploads\/2024\/05\/table.png\" "\\"table")
<\/figure>\n\n\n\n![\"cooperation](\"\/app\/uploads\/2024\/05\/interested_in_cooperation_.png\")
<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"