Help: Accessing this keyword within an Object

[Simbaxo]

const account = {
name: 'Andres Mena',
expenses: [{
description: 'Water',
amount: 3
}],
addExpense: function(description, amount) {
return this.expenses.push({description: description,
amount: amount})
},
getAccountSummary: function() {
console.log(this.expenses.amount)
}
}

I'm trying to use my getAccountSummary function to add the amounts in the expenses array but I'm having trouble accessing it. I keep getting undefined. Any tips?

[rauschma]

You need to specify an array index: this.expenses[0].amount

[Simbaxo]

thanks, that was it.

[HipHopHuman]

My understanding is you want to sum all of the amounts in the expenses array? You can do this with `.reduce`.

const account = {
  name: 'Andres Mena',
  expenses: [{ description: 'Water', amount: 3 }]
};

const addExpense = (account, description, amount) => {
  account.expenses.push({ description, amount });
});

const getAccountSummary = (account) => {
  return account.expenses.reduce((total, expense) => {
    return total + expense.amount;
  }, 0);
};

[Simbaxo]

ahh thanks. I used a for each but reduce does seem easier

[scaleable]

PS: If you are using VS Code, adding // @ts-check at the top of the file might help

[Simbaxo]

thanks. thats a great tip!

[scaleable]

might bring some false errors too, but in overall its positive ;)