bak-lib

This is a small utility package to test npm

These are the current functions in the library

• Append
• Box
• Compose
• Curry
• Maybe
• prop
• Queue
• Stack

Append

  expect(append("thing")("some")).toEqual("something");

Box

this function can be used to map over complex data to filter out the results

    const items = box(data)
      .map((x) => x.filter((i) => i.dept === 1))
      .map((x) => x.filter((i) => i.vendor === 1))
      .map((x) => x.filter((i) => i.category === 1))
      .map((x) => x.filter((i) => i.price > 2.0))
      .map((x) => x.filter((i) => i.price < 3.0))
      .fold((x) => x);

Compose

This function is used to compose other functions in a chainable point free fashion

  const addOne = (x) => x.map((y) => y + 1);
  const addTwo = (x) => x.map((y) => y + 2);

    const result = compose(addOne, addTwo);
    expect(result(arr)).toEqual([4, 5, 6, 7, 8, 9]);

Curry

This function can be used like Partial Applicatoin. You can lazily load arguments and when the function has received all the neccessary arguments, then it will run the function

    const curriedSum = curry(sum);
    expect(curriedSum(4)(5)).toEqual(9);

    const curriedSum = curry(sum);
    const fn1 = curriedSum(4);
    const result = fn1(5);
    expect(result).toEqual(9);

Prop

This function get a property from an object

    const obj = { id: 1, name: "ben" };
    expect(prop("name")(obj)).toEqual("ben");

Maybe

This modan can be used when a null value could be expexted from data recieved from server

    const maybeNumberOne = Maybe.just(5);
    const maybeNumberTwo = Maybe.nothing();

    expect(maybeNumberOne.isNothing()).toBeFalsy();
    expect(maybeNumberTwo.isNothing()).toBeTruthy();

Queue

This is a first in first out data structure

  const queue = new Queue<string>();
    queue.enqueue("a");
    queue.enqueue("b");
    const result = queue.dequeue();
    expect(result).toEqual("a");
    expect(queue.size()).toEqual(1);

Stack

this is a first in first out data structure

   const stack = new Stack<string>();
    stack.push("a");
    expect(stack.size()).toEqual(1);
    expect(stack.peek()).toEqual("a");
    stack.pop();
    expect(stack.size()).toEqual(0);