2-piping.js

/*
  PIPING FUNCTIONS
  ================
  1. Write 3 functions:
  - one that adds 2 numbers together
  - one that multiplies 2 numbers together
  - one that formats a number so it's returned as a string with a £ sign before it (e.g. 20 -> £20)

  2. Using the variable startingValue as input, perform the following operations using your functions all
  on one line (assign the result to the variable badCode):
  - add 10 to startingValue
  - multiply the result by 2
  - format it
  
  3. Write a more readable version of what you wrote in step 2 under the BETTER PRACTICE comment. Assign
  the final result to the variable goodCode
*/

function add(a,b) {
  return a + b ;

}


function multiply(a,b) {
  return a*b ;

}

function format(a) {

  return `£${a}`

}

const startingValue = 2

// Why can this code be seen as bad practice? Comment your answer.
let badCode = format(multiply(add(startingValue, 10 ), 2));

/* BETTER PRACTICE */
let adds= add(startingValue,10);
let multiplies = multiply(adds , 2);


let goodCode = format(multiplies);

/* ======= TESTS - DO NOT MODIFY ===== 
There are some Tests in this file that will help you work out if your code is working.

To run these tests type `node 2-piping.js` into your terminal
*/

const util = require('util');

function test(test_name, actual, expected) {
    let status;
    if (actual === expected) {
        status = "PASSED";
    } else {
        status = `FAILED: expected: ${util.inspect(expected)} but your code returned: ${util.inspect(actual)}`;
    }

    console.log(`${test_name}: ${status}`);
}

test('add function - case 1 works', add(1,3), 4)
test('add function - case 2 works', add(2.4,5), 7.4)
test('multiply function works', multiply(2,3), 6)
test('format function works', format(16), "£16")
test('badCode variable correctly assigned', badCode, "£24")
test('goodCode variable correctly assigned', goodCode, "£24")