Operations

Extcy Operations

In this chapter, we will learn how to use operations such as pattern matching, cond, pipe'ing and more.

Pattern Matching

const person1 = {
    name: "Alice",
    age: 30,
    address: {
        city: "San Francisco",
        state: "California",
    },
};
 
const pattern1 = {
    name: "Alice",
    age: (age: number) => age >= 30,
    address: { state: "California" },
};
console.log(match(person1, pattern1)); // true

The match operator is not only used to match against simple values, but it is also useful for destructuring more complex data types.

When

const result = when(
    11,
    [(n) => n === 0, () => "zero"],
    [(n) => n % 2 === 0, () => "even"],
    [(n) => n % 2 !== 0, () => "odd"]
);
 
console.log(result); // odd

Cond

const result = cond<number>(3,
	{ predicate: (value) => value === 1, result: 'one' },
	{ predicate: (value) => value === 2, result: 'two' },
	{ predicate: (value) => value === 3, result: 'three' },
	{ predicate: (value) => value === 4, result: 'four' },
	{ predicate: (value) => value === 5, result: 'five' },
);
 
console.log(result); // => "three"

Pipe

// functions for numbers
const addOne = (n: number) => n + 1;
const double = (n: number) => n * 2;
const square = (n: number) => n * n;
 
// functions for strings
const concatenate = (s: string) => s + ' World';
const toUpperCase = (s: string) => s.toUpperCase();
 
// functions for arrays
const reverseArray = (arr: unknown[]) => [...arr].reverse();
const sortArray = (arr: unknown[]) => [...arr].sort();
 
// numbers
const result1 = pipe<number>(addOne, double, square)(3);
console.log(result1); // => 64
 
// strings
const result2 = pipe<string>(concatenate, toUpperCase)('Hello');
console.log(result2); // => "HELLO WORLD"
 
// arrays
const result3 = pipe<unknown[]>(reverseArray, sortArray)([4, 6, 5, 2]);
console.log(result3); // => "[2, 4, 5, 6]"

Sigil

const capitalizedWords = sigil(/([A-Z]\w+)/g, "hello world this is a test");
const numbers = sigil(/\d+/g, "I have 3 apples and 5 oranges.");
    
console.log(capitalizedWords); // ["Hello", "World", "This", "Is", "A", "Test"]
console.log(numbers); // ["3", "5"]

🥳 Awesome! Remember that these are just really simple examples. If you want to see more examples, feel free to check out example folder.

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