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Nick Leeman 2023-04-03 13:57:42 +02:00
commit afe595f403
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*.js

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type FunType<input, output> = {
(inputValue: input): output;
next: <nextOuput>(nextFunction: FunType<output, nextOuput>) => FunType<input, nextOuput>;
repeat: (this: FunType<input, input>, count: number) => FunType<input, input>;
repeatUntil: (this: FunType<input, input>, condition: FunType<input, boolean>) => FunType<input, input>;
}
const Fun = <input, output>(inputLamba: (_: input) => output): FunType<input, output> => {
const func = inputLamba as FunType<input, output>;
func.next = function<nextOutput>(nextFunction: FunType<output, nextOutput>): FunType<input, nextOutput> {
return Fun(inputValue => nextFunction(inputLamba(inputValue)));
}
func.repeat = function(this: FunType<input, input>, count: number): FunType<input, input> {
if (count == 0) {
return Fun((x: input) => x);
}
return this.next(this.repeat(count - 1));
}
func.repeatUntil = function(this: FunType<input, input>, condition: FunType<input, boolean>): FunType<input, input> {
return Fun((x: input) => {
if (condition(x)) {
return x;
}
console.log(x);
return this.next(this.repeatUntil(condition))(x);
})
// Shorthand
// return Fun((x: input) => condition(x) ? x : this.next(this.repeatUntil(condition))(x));
}
return func;
}
const Conditional = function<input, output>(_if: FunType<input, boolean>, _then: FunType<input, output>, _else: FunType<input, output>): FunType<input, output> {
return Fun((x) => {
if (_if(x)) {
return _then(x);
} else {
return _else(x);
}
})
}
//
// Some FunType lamdas
//
const isPositive: FunType<number, boolean> = Fun((x: number) => x > 0);
const isEven: FunType<number, boolean> = Fun((x: number) => x % 2 == 0);
const incr: FunType<number, number> = Fun((x: number) => x + 1);
const double: FunType<number, number> = Fun((x: number) => x * 2);
const decr: FunType<number, number> = Fun((x: number) => x - 1);
const convert: FunType<number, string> = Fun((x: number) => String(x));
const exclaim: FunType<string, string> = Fun((x: string) => x + "!");
const saveSqrt = Fun((a: number) => a > 0 ? Math.sqrt(a) : Math.abs(Math.sqrt(a)));
//
// Generic id functions
//
// Id functions do basically nothing but initialize a base where we can work from (initializing a pipeline for example)
// Eg. Id functions are the base of all other functions
// const id: <a>() => FunType<a, a> = () => Fun(x => x);
function id<a>(): FunType<a, a> {
return Fun(_ => _);
}
// Another way of writing this functions
const genericId = <a>(): FunType<a, a> => Fun(_ => _);
// Even one more way of writing this function
const genericId2 = function<a>(): FunType<a, a> {
return Fun(_ => _);
}
// Example usage 1
let exampleId = id<number>().next(incr).next(incr)(0) // -> result would be 2
// |
// Define type here
// Id functions but for a specific type (Non generic)
type Unit = {};
const idNum: FunType<Unit, number> = Fun(_ => 0);
const idString: FunType<Unit, string> = Fun(_ => "");
// |
// Define type here
// Example usage 2
let exampleId2 = idNum.next(incr).next(incr)(0)
//
// Countainers / Functors
//
// A functor is a container that is mappable
// Aka: We can run map functions on the containers itself to perform some kind of data update.
type Countainer<content> = {
content: content; // Content
counter: number; // For Example: amount of times object has been changed or mapped.
}
// Increments the value of counter with 1
function incrCountainer<content>(countainer: Countainer<content>): Countainer<content> {
return {
content: countainer.content,
counter: countainer.counter + 1
};
}
// Applies transformer lamda to content of countainer to potentionally map value to other type: content -> newContent
function mapCountainerNoFun<content, newContent>(countainer: Countainer<content>, transformer: FunType<content, newContent>): Countainer<newContent> {
return {
counter: countainer.counter + 1,
content: transformer(countainer.content)
}
}
// Applies transformer lamda to each element content of array to potentionally map value to other type: content -> newContent
function mapArray<content, newContent>(transformer: FunType<content, newContent>): FunType<Array<content>, Array<newContent>> {
return Fun((array: Array<content>) => array.map(transformer));
}
// Applies transformer lamda to content of countainer to potentionally map value to other type: content -> newContent
// !! But is wrapped in the FunType so we can use this in a pipeline !!
function mapCountainer<content, newContent>(transformer: FunType<content, newContent>): FunType<Countainer<content>, Countainer<newContent>> {
return Fun(c => {
return {
counter: c.counter + 1,
content: transformer(c.content)
}
})
}
type Message = {
username: string;
likes: number;
message: string;
}
// Some pipeline functions for Message type
const setUsername = (newUsername: string) => Fun<Message, Message>(c => ({ username: newUsername, likes: c.likes, message: c.message }));
const incrLikes = () => Fun<Message, Message>(c => ({ username: c.username, likes: c.likes + 1, message: c.message }));
// We could also write these functions like this
function setMessage (msg: string): FunType<Message, Message> {
return Fun(c => {
return {
username: c.username,
likes: c.likes,
message: msg
}
})
}
// Countainer where content is of Message Type
let messageCountainer: Countainer<Message> = {
counter: 0,
content: {
username: "",
likes: 0,
message: ""
}
}
// Pipeline usage example with countainer and message
// Using mapCountainer
const messagePipeline1 = mapCountainer(
setUsername("Test")
.next(setMessage("This is a message"))
.next(incrLikes())
.next(incrLikes())
)
const messagePipeline2 = mapCountainer(
setUsername("Test2")
.next(setMessage("This is a new and more improved message message"))
.next(incrLikes())
.next(incrLikes())
.next(incrLikes())
)
const message1 = messagePipeline1(messageCountainer);
const message2 = messagePipeline2(messageCountainer);
//console.log(message1);
// Result: {
// counter: 1,
// content: { username: 'Test', likes: 2, message: 'This is a message' }
// }
// This function will increase all the likes by 1 in a array of Countainers where its type is Message
// We use the MapArray function for this operation
const increaseAllLikes: FunType<Array<Countainer<Message>>, Array<Countainer<Message>>> = mapArray(mapCountainer(incrLikes()));
// Create array
const messages: Array<Countainer<Message>> = [message1, message2];
// console.log(increaseAllLikes(messages));
// Result: [
// {
// counter: 2,
// content: { username: 'Test', likes: 3, message: 'This is a message' }
// },
// {
// counter: 2,
// content: {
// username: 'Test2',
// likes: 4,
// message: 'This is a new and more improved message message'
// }
// }
// ]
// Some more examples of array mapping
// Basic increment
// console.log(
// mapArray(incr)([1, 2, 3, 4])
//)
// Result: [ 2, 3, 4, 5 ]
// Increment, double and decrement in pipeline
// console.log(
// mapArray(incr.next(double).next(decr))([1, 2, 3, 4])
// )
// Result: [ 3, 5, 7, 9 ]
// Increment, check if even.
// Here we also perform a mapping function that will change the type of content
// console.log(
// mapArray(incr.next(isEven))([1, 2, 3, 4])
// )
// Result: [ true, false, true, false ]
//
// Monoid / Monoidal structure / Monoids
//
// Monoids are datatypes (structures) that supports a given mathematical operation plus some given values
// Examples:
// + (Operator in numerical context)
// 1 + 2 == 2 + 1
// (a + b) * c == c * (b + a)
// a + 0 == 0 + a == a
// * (Operator in numerical context)
// (a * b) * c == a * (b * c)
// a * 1 == 1 * a == a
// + (Operator in string context)
// (a + b) + c == a + (b + c)
// a + "" == "" + a == a
// Practical examples with arrays
const numArray1: Array<number> = [1, 2, 3];
const numArray2: Array<number> = [2, 3, 4];
const numArray3: Array<number> = [5, 6, 7];
const numArray4: Array<number> = [];
const resultNumArr1 = numArray1.concat(numArray2.concat(numArray3)); // -> [1, 2, 3, 2, 3, 4, 5, 6, 7]
const resultNumArr2 = numArray1.concat(numArray2).concat(numArray3); // -> [1, 2, 3, 2, 3, 4, 5, 6, 7]
const resultNumArr3 = (numArray1.concat(numArray2)).concat(numArray3); // -> [1, 2, 3, 2, 3, 4, 5, 6, 7]
// Therefore: resultNumArr1 == resultNumArr2 == resultNumArr31
const resultNumArr4 = numArray4.concat(numArray1); // -> [1, 2, 3]
const resultNumArr5 = numArray1.concat(numArray4); // -> [1, 2, 3]
// Therefore: resultNumArr4 == resultNumArr5
// This type of reasoning also applies to (monoidal) functions!!
// Here monoids come into play
let monoidTest1 = id<number>().next(incr).next(incr).next(incr) (0);
let monoidTest2 = id<number>().next(incr.next(incr).next(incr)) (0);
let monoidTest3 = id<number>().next(incr.next(incr)).next(incr) (0);
// Therefore: monoidTest1 == monoidTest2 == monoidTest3
let monoidTest4 = incr.next(id<number>()) (0);
let monoidTest5 = id<number>().next(incr) (0);
// Therefore: monoidTest4 == monoidTest5
// A monoido or triple is
// A type T
// An operator + : [T, T] => T
// An element z : T
//
// Such that:
// (a + b) + c == a + (b + c) <--- associative law
// a + z == z + a == a <--- identity law
//
// Monads are different than monoids!
// Monads (NOT Monoid / Monodial, etc) are Functors and Monoids combined!
//
type Pair<a, b> = {
fst: a,
snd: b
}
const myPair: Pair<number, string> = {
fst: 1,
snd: "Hello"
}
function pairFst<a, b>(): FunType<Pair<a, b>, a> {
return Fun((pair: Pair<a, b>) => {
return pair.fst;
})
}
const pairSnd = function<a, b>(): FunType<Pair<a, b>, b> {
return Fun((pair: Pair<a, b>) => {
return pair.snd;
})
}
const pairMap = function<a, b, a1, b1>(f1: FunType<a, a1>, f2: FunType<b, b1>): FunType<Pair<a, b>, Pair<a1, b1>> {
return Fun((pair: Pair<a, b>) => {
return {
fst: f1(pair.fst),
snd: f2(pair.snd)
}
})
}
type WithNum<a> = Pair<a, number>;
const withNumSingle: WithNum<string> = {
fst: "yeey",
snd: 3
}
const withNumDouble: WithNum<WithNum<string>> = {
fst: {
fst: "Hoi!",
snd: 3,
},
snd: 1,
}
const mapWithNum = function<a, b>(f: FunType<a, b>): FunType<WithNum<a>, WithNum<b>> {
return pairMap(f, id<number>());
}
const joinWithNum = function<a>(): FunType<WithNum<WithNum<a>>, WithNum<a>> {
return Fun(num => {
return {
fst: num.fst.fst,
snd: num.snd + num.fst.snd
}
})
}
const incrementWithNum = function<a>(): FunType<WithNum<a>, WithNum<a>> {
return Fun((num: WithNum<a>) => {
return {
fst: num.fst,
snd: num.snd + 1
}
})
}
console.log(
joinWithNum().next(incrementWithNum()).next(incrementWithNum()) (withNumDouble)
);
const test123 = "sdsdds";

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{
"name": "school-zooi",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
"author": "",
"license": "ISC"
}

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{
"compilerOptions": {
/* Visit https://aka.ms/tsconfig to read more about this file */
/* Projects */
// "incremental": true, /* Save .tsbuildinfo files to allow for incremental compilation of projects. */
// "composite": true, /* Enable constraints that allow a TypeScript project to be used with project references. */
// "tsBuildInfoFile": "./.tsbuildinfo", /* Specify the path to .tsbuildinfo incremental compilation file. */
// "disableSourceOfProjectReferenceRedirect": true, /* Disable preferring source files instead of declaration files when referencing composite projects. */
// "disableSolutionSearching": true, /* Opt a project out of multi-project reference checking when editing. */
// "disableReferencedProjectLoad": true, /* Reduce the number of projects loaded automatically by TypeScript. */
/* Language and Environment */
"target": "es2016", /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
// "lib": [], /* Specify a set of bundled library declaration files that describe the target runtime environment. */
// "jsx": "preserve", /* Specify what JSX code is generated. */
// "experimentalDecorators": true, /* Enable experimental support for TC39 stage 2 draft decorators. */
// "emitDecoratorMetadata": true, /* Emit design-type metadata for decorated declarations in source files. */
// "jsxFactory": "", /* Specify the JSX factory function used when targeting React JSX emit, e.g. 'React.createElement' or 'h'. */
// "jsxFragmentFactory": "", /* Specify the JSX Fragment reference used for fragments when targeting React JSX emit e.g. 'React.Fragment' or 'Fragment'. */
// "jsxImportSource": "", /* Specify module specifier used to import the JSX factory functions when using 'jsx: react-jsx*'. */
// "reactNamespace": "", /* Specify the object invoked for 'createElement'. This only applies when targeting 'react' JSX emit. */
// "noLib": true, /* Disable including any library files, including the default lib.d.ts. */
// "useDefineForClassFields": true, /* Emit ECMAScript-standard-compliant class fields. */
// "moduleDetection": "auto", /* Control what method is used to detect module-format JS files. */
/* Modules */
"module": "commonjs", /* Specify what module code is generated. */
// "rootDir": "./", /* Specify the root folder within your source files. */
// "moduleResolution": "node", /* Specify how TypeScript looks up a file from a given module specifier. */
// "baseUrl": "./", /* Specify the base directory to resolve non-relative module names. */
// "paths": {}, /* Specify a set of entries that re-map imports to additional lookup locations. */
// "rootDirs": [], /* Allow multiple folders to be treated as one when resolving modules. */
// "typeRoots": [], /* Specify multiple folders that act like './node_modules/@types'. */
// "types": [], /* Specify type package names to be included without being referenced in a source file. */
// "allowUmdGlobalAccess": true, /* Allow accessing UMD globals from modules. */
// "moduleSuffixes": [], /* List of file name suffixes to search when resolving a module. */
// "resolveJsonModule": true, /* Enable importing .json files. */
// "noResolve": true, /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */
/* JavaScript Support */
// "allowJs": true, /* Allow JavaScript files to be a part of your program. Use the 'checkJS' option to get errors from these files. */
// "checkJs": true, /* Enable error reporting in type-checked JavaScript files. */
// "maxNodeModuleJsDepth": 1, /* Specify the maximum folder depth used for checking JavaScript files from 'node_modules'. Only applicable with 'allowJs'. */
/* Emit */
// "declaration": true, /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
// "declarationMap": true, /* Create sourcemaps for d.ts files. */
// "emitDeclarationOnly": true, /* Only output d.ts files and not JavaScript files. */
// "sourceMap": true, /* Create source map files for emitted JavaScript files. */
// "outFile": "./", /* Specify a file that bundles all outputs into one JavaScript file. If 'declaration' is true, also designates a file that bundles all .d.ts output. */
// "outDir": "./", /* Specify an output folder for all emitted files. */
// "removeComments": true, /* Disable emitting comments. */
// "noEmit": true, /* Disable emitting files from a compilation. */
// "importHelpers": true, /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
// "importsNotUsedAsValues": "remove", /* Specify emit/checking behavior for imports that are only used for types. */
// "downlevelIteration": true, /* Emit more compliant, but verbose and less performant JavaScript for iteration. */
// "sourceRoot": "", /* Specify the root path for debuggers to find the reference source code. */
// "mapRoot": "", /* Specify the location where debugger should locate map files instead of generated locations. */
// "inlineSourceMap": true, /* Include sourcemap files inside the emitted JavaScript. */
// "inlineSources": true, /* Include source code in the sourcemaps inside the emitted JavaScript. */
// "emitBOM": true, /* Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files. */
// "newLine": "crlf", /* Set the newline character for emitting files. */
// "stripInternal": true, /* Disable emitting declarations that have '@internal' in their JSDoc comments. */
// "noEmitHelpers": true, /* Disable generating custom helper functions like '__extends' in compiled output. */
// "noEmitOnError": true, /* Disable emitting files if any type checking errors are reported. */
// "preserveConstEnums": true, /* Disable erasing 'const enum' declarations in generated code. */
// "declarationDir": "./", /* Specify the output directory for generated declaration files. */
// "preserveValueImports": true, /* Preserve unused imported values in the JavaScript output that would otherwise be removed. */
/* Interop Constraints */
// "isolatedModules": true, /* Ensure that each file can be safely transpiled without relying on other imports. */
// "allowSyntheticDefaultImports": true, /* Allow 'import x from y' when a module doesn't have a default export. */
"esModuleInterop": true, /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */
// "preserveSymlinks": true, /* Disable resolving symlinks to their realpath. This correlates to the same flag in node. */
"forceConsistentCasingInFileNames": true, /* Ensure that casing is correct in imports. */
/* Type Checking */
"strict": true, /* Enable all strict type-checking options. */
// "noImplicitAny": true, /* Enable error reporting for expressions and declarations with an implied 'any' type. */
// "strictNullChecks": true, /* When type checking, take into account 'null' and 'undefined'. */
// "strictFunctionTypes": true, /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
// "strictBindCallApply": true, /* Check that the arguments for 'bind', 'call', and 'apply' methods match the original function. */
// "strictPropertyInitialization": true, /* Check for class properties that are declared but not set in the constructor. */
// "noImplicitThis": true, /* Enable error reporting when 'this' is given the type 'any'. */
// "useUnknownInCatchVariables": true, /* Default catch clause variables as 'unknown' instead of 'any'. */
// "alwaysStrict": true, /* Ensure 'use strict' is always emitted. */
// "noUnusedLocals": true, /* Enable error reporting when local variables aren't read. */
// "noUnusedParameters": true, /* Raise an error when a function parameter isn't read. */
// "exactOptionalPropertyTypes": true, /* Interpret optional property types as written, rather than adding 'undefined'. */
// "noImplicitReturns": true, /* Enable error reporting for codepaths that do not explicitly return in a function. */
// "noFallthroughCasesInSwitch": true, /* Enable error reporting for fallthrough cases in switch statements. */
// "noUncheckedIndexedAccess": true, /* Add 'undefined' to a type when accessed using an index. */
// "noImplicitOverride": true, /* Ensure overriding members in derived classes are marked with an override modifier. */
// "noPropertyAccessFromIndexSignature": true, /* Enforces using indexed accessors for keys declared using an indexed type. */
// "allowUnusedLabels": true, /* Disable error reporting for unused labels. */
// "allowUnreachableCode": true, /* Disable error reporting for unreachable code. */
/* Completeness */
// "skipDefaultLibCheck": true, /* Skip type checking .d.ts files that are included with TypeScript. */
"skipLibCheck": true /* Skip type checking all .d.ts files. */
}
}