String Calculator Kata in NodeJS

Your goal is to create a program that reads numbers in a string and produce their sum following the TDD flow:

Write a test that fails
Make the most straightforward change to make the test pass
Optionally, refactor your code

On every step, try hard to make the smallest change possible. The goal is not to complete the list of features but deliberate practice of the best programming practices you know of.

Sequence of features to implement

Please, try to think the smallest increments you can work on:

An empty string input must produce 0
An input string with a single number must produce that number
An input string with more than one number separated by commas must produce their sum Example: "1,2" must produce 3
Now numbers can be separated also by the newline character Example: "1\n2" must produce 3
Now a custom delimiter can be defined by prefixing the input string with //<DELIMITER>\n<NUMBERS> Example: "//;\n1;2" must produce 3
Now the program needs to fail with a message when there's a negative number in the input string. The error message must include the list of offending numbers
Now the program needs to ignore any number greater than 1000
Now a custom delimiter of any length can be defined by prefixing the input string with //[<DELIMITER>]\n<NUMBERS> Example: "//[|||]\n1|||2|||3 must produce 6
Now multiple delimiters can be defined by prefixing the input string with //[<DELIMITER>][<DELIMITER>]\n<NUMBERS> Example: "//[|][;;]\n1|2;;3 must produce 6

Preparing your environment

You can skip steps 1 and 2 if your development environment already has NodeJS 15 set up. Check the .tool-versions file to know the specific NodeJS version this repo requires.

Install asdf
Add the NodeJS plugin to asdf with asdf plugin add nodejs

Fork this repo, clone it somewhere in your computer, and run asdf install and npm install where you cloned it.

Example:

~ git clone git@github.com:<YOUR GITHUB USERNAME>/nodejs-string-calculator.git
Cloning into 'nodejs-string-calculator'...
remote: Enumerating objects: 5, done.
remote: Counting objects: 100% (5/5), done.
remote: Compressing objects: 100% (5/5), done.
remote: Total 5 (delta 0), reused 0 (delta 0), pack-reused 0
Receiving objects: 100% (5/5), 5.33 KiB | 2.67 MiB/s, done.
~ cd nodejs-string-calculator
~/nodejs-string-calculator asdf install
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  3490    0  3490    0     0   8574      0 --:--:-- --:--:-- --:--:--  8553
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 29.1M  100 29.1M    0     0  8835k      0  0:00:03  0:00:03 --:--:-- 8835k
node-v15.14.0-darwin-x64.tar.gz: OK
~/nodejs-string-calculator $ npm install
npm WARN deprecated request-promise-native@1.0.9: request-promise-native has been deprecated because it extends the now deprecated request package, see https://github.com/request/request/issues/3142
npm WARN deprecated urix@0.1.0: Please see https://github.com/lydell/urix#deprecated
npm WARN deprecated har-validator@5.1.5: this library is no longer supported
npm WARN deprecated resolve-url@0.2.1: https://github.com/lydell/resolve-url#deprecated
npm WARN deprecated request@2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142

added 537 packages, and audited 538 packages in 3s

24 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities

Test your environment by running the tests with npm run test

Example:


> nodejs-string-calculator@1.0.0 test
> node --experimental-vm-modules node_modules/.bin/jest

(node:57454) ExperimentalWarning: VM Modules is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
 FAIL  test/foo_test.js
  ✕ adds 1 + 2 to equal 3 (5 ms)

  ● adds 1 + 2 to equal 3

    expect(received).toBe(expected) // Object.is equality

    Expected: 5
    Received: 3

      2 |
      3 | test('adds 1 + 2 to equal 3', () => {
    > 4 |     expect(sum(1, 2)).toBe(5);
        |                       ^
      5 | });

      at Object.<anonymous> (test/foo_test.js:4:23)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        0.689 s, estimated 1 s
Ran all test suites.

julen9601/nodejs-string-calculator

String Calculator Kata in NodeJS

Sequence of features to implement

Preparing your environment