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https://github.com/petarsimonovic/bank
https://github.com/petarsimonovic/bank
Last synced: 9 days ago
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- Host: GitHub
- URL: https://github.com/petarsimonovic/bank
- Owner: PetarSimonovic
- Created: 2021-03-08T11:07:51.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2021-03-11T14:11:58.000Z (over 3 years ago)
- Last Synced: 2023-02-27T13:18:52.430Z (over 1 year ago)
- Language: JavaScript
- Size: 104 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Bank tech test
### Requirements
* Interact with your code via a REPL like IRB or the JavaScript console. (You don't need to implement a command line interface that takes input from STDIN.)
* Deposits, withdrawal.
* Account statement (date, amount, balance) printing.
* Data can be kept in memory (it doesn't need to be stored to a database or anything).
### Acceptance criteria
**Given** a client makes a deposit of 1000 on 10-01-2012
**And** a deposit of 2000 on 13-01-2012
**And** a withdrawal of 500 on 14-01-2012
**When** she prints her bank statement
**Then** she would see
```
date || credit || debit || balance
14/01/2012 || || 500.00 || 2500.00
13/01/2012 || 2000.00 || || 3000.00
10/01/2012 || 1000.00 || || 1000.00
```
### Instructions
- run ```npm install``` in the command line to install dependencies
- run ```npm test``` to execute tests and generate coverage details.
- The app functions in the browser console. It has no HTML interface.
### Instructions
1. bank = new Bank()
**deposits and withdrawal**
To make a deposit or withdrawal, provide a date (as a string in DD/MM/YYYY or DD-MM-YYYY format) and a numerical value with two decimal places. Do not include a currency symbol or currency code.
```js
bank.deposit("31/12/2020", 1000.00)
bank.withdrawal("31/12/2020", 1000.00)
```
**statement**
Use statement to print out a list of transactions in reverse order, formatted in line with the brief's requirements.
```js
bank.statement
```
### Functionality
1. **Account** array:
- Stores details of transaction activity as a string.
- Each transaction has a date, an amount and a balance. Transaction formatting indicates whether it is a deposit or withdrawal.
2. **Balance** variable:
- Stores the account holder's balance as a numerical value with two decimal places.
3. **Withdrawal** function:
- Accepts two arguments: date and amount
- Updates account to reflect the transaction.
4. **Deposit** function:
- Accepts two arguments: date and amount
- Updates account to reflect the transaction.
5. **Statement** function:
- Generates and returns a statement in line with given format.
### Functions
This solution attempts to keep functions DRY and adhere to SRP.
**deposit**
Updates the account for a credit transaction
**withdrawal**
Updates the account for a debit transaction
**balanceUpdate**
Updates balance for both credit and debit transactions, taking account of decimal places and trailing zeroes
**addDecimal**
Returns decimal to balance, accounting for trailing zeroes
**statement**
Prints a statement with a header
**checkValidity**
Uses checkDate and checkAmount to perform some basic edge case checks
**checkDate**
Checks the date; throws dateError if it detects an issue
**checkAmount**
Checks the amount is a number; throws amountError if it detects an issue
**dateError**
Raises an error if a date is not a date (according to checkDate)
**amountError**
Raises an error if an amount is not a number (according to checkAmount)
### Considerations
**Refactoring deposit and withdrawal**
Deposit and Withdrawal functions could be combined into a single "Transaction" function that accepts both positive and negative amounts as arguments, then assigns a "credit" or "debit" status respectively.
This could streamline the code base, reducing the number of functions.
However, "Deposit" and "Withdrawal" are specific actions with unique names. As a result, they reduce the potential for ambiguity among users that could arise from a more-generic "Transaction" function.
**Decimals**
Javascript's removal of trailing zeroes following a decimal raises a number of challenges in formatting the statement. The zeroes can be retained using ```toFixed(2)```, converting the number into a string. However, this approach then prevents accurate addition and subtraction using that converted sum.
The solution applied here is to remove decimals by multiplying all amounts by 100. This allows decimals to be reinstated when printing the statement in a way that accounts for trailing zeroes yet allows the balance to be updated accurately.
### Edge cases
- This solution offers some limited checks and balances against input edge cases.
It will:
- check if an amount provided is a number
- check whether the date provided has numerical values for days, months and years.
The date checking process will allow users to input dates using any separator (including DD-MM-YYYY, DD.MM.YYYY ) and will standardise to DD/MM/YYYY.
### Known issues
- The statement cannot yet be sorted by date: it outputs debits and credits in the order they are made, not by the date the user provides.
To resolve this issue, the ```checkDate``` function could be repurposed to create a timestamp that could be attached to each entry, allowing the account array to be sorted, eg:
```js
this.validDate = `${year}${month}${day}`
```
- Dates must be entered as strings, while amounts are entered as numeric values. This is cumbersome and confusing from a user perspective.
- There is no default date at present - the solution could assign the current system date as a default.
### Tech stack
- Written in javascript
- Testing in Jasmine and Karma
- linting in ESlint