How to validate if sum of values are equal in Validation - laravel

Question

I have this accounting project where I need to validate if debit and credit are equal before saving to the database.
e.g
accounts: [
{
id: 1,
account_id: 1,
debit: 1000
},
{
id: 2,
account_id: 5,
credit: 1500
},
{
id: 3,
account_id: 8,
debit: 500
}
]
By the way I am using axios and lodash.
axios.post('/api/journals', {
accounts : map(this.accounts, function(account) {
account_id: account.account_id,
debit: account.debit,
credit: account.credit
})
}
Can anyone suggest how to implement this validation rule.

Answer 1

The validation rule has nothing to do with Laravel or VueJS. All you need is to use lodash to iterate through your accounts array, sum the debit and credit numbers separately, and compare them thereafter:
var debitSum = _.reduce(data.accounts, function(sum, account) {
return (account.debit || 0) + sum;
}, 0);
var creditSum = _.reduce(data.accounts, function(sum, account) {
return (account.credit || 0) + sum;
}, 0);
console.log('Debit: ' + debitSum + '; Credit: ' + creditSum);
if (debitSum !== creditSum) {
// Debit and credit sums do not match
} else {
// Debit and credit sums match
}
The code above uses the _.reduce() method to calculate the sum of debit/credit amounts. Since debit and credit keys are not guanranteed to be present all the time, we use the || operator to assign a value of 0 when it is falsy (e.g. undefined, null, 0, empty string, etc.)
Here's a proof-of-concept example:
var data = { accounts: [{
id: 1,
account_id: 1,
debit: 1000
},
{
id: 2,
account_id: 5,
credit: 1500
},
{
id: 3,
account_id: 8,
debit: 500
}
]};
var debitSum = _.reduce(data.accounts, function(sum, account) {
return (account.debit || 0) + sum;
}, 0);
var creditSum = _.reduce(data.accounts, function(sum, account) {
return (account.credit || 0) + sum;
}, 0);
console.log('Debit: ' + debitSum + '; Credit: ' + creditSum);
if (debitSum !== creditSum) {
console.log('Debit and credit are not equal!');
} else {
console.log('All ok');
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js"></script>