js-katas-solutions for: https://github.com/shanebarringer/js-katas

00-convertToNumbers.js

// Write a function named convert() that takes string values and changes each value to number, and returns a single array

const convert = (...values) => {
  return values.map(v => parseInt(v, 10)).filter(num => !isNaN(num));
};

module.exports = convert;

01-convertAndAdd.js

/* Building on the previous convert function...
  Write a function named convertAndAdd() that that takes multiple values and adds them together, returning a single value
 
  For example: 
  convertAndAdd("5", 10, "20") => 35
*/

const convert = require("./00-convertToNumbers");

const convertAndAdd = (...values) => {
  return convert(...values).reduce((acc, curr) => acc + curr, 0);
};

module.exports = convertAndAdd;

02-combine.js

// Write a function named combine() that takes two arguments and returns a single array

const combine = (first, ...rest) =>
  [first, ...rest].reduce((acc, curr) => acc.concat(curr), []);

module.exports = combine;

03-removeDuplicates.js

// write a function that returns a single array without duplicates

const removeDuplicates = (...values) => {
  return [...new Set(values.reduce((acc, curr) => acc.concat(curr), []))];
};

module.exports = removeDuplicates;

04-last.js

// Find the last element of a list.

// Example:
// last( [1,2,3,4] ) // => 4
// last( 1,2,3,4 )   // => 4

const last = (...val) => {
  const combinedArray = val.reduce((acc, curr) => acc.concat(curr), []);
  return combinedArray[combinedArray.length - 1];
};

module.exports = last;

05-keysAndValues.js

/* Create a function named keysAndValues() that takes an object and returns returns a two-dimensional array containing an array of keys, and a separate array of values

    For Example:
    keysAndValues({firstName: "Foo", lastName: "Bar"}) => [["firstName", "lastName"], ["Foo", "Bar"]]
*/

const keysAndValues = obj => {
  const keys = Object.keys(obj);
  const values = Object.values(obj);
  return [keys, values];
};

module.exports = keysAndValues;