CODEWITHSUNDEEP
javascriptobjectpropertiesadditionnumeric
J.Edge
J.Edge

Reputation: 49

Why can't I add to a numeric object property?

If I have a simple object like this:

const currentAccount = [{
    name: 'J.Edge',
    balance: 100,

}]

Firstly, am I right in thinking (forgive my newbie-ness, only been learning JS for a few weeks) that I can't add to the numeric balance property directly, like in the function below, because of JS type coercion converting the balance property's 100 to a string?

const withdraw = (amount) => {
    currentAccount.balance - amount
    return Object.keys(currentAccount)

}

And secondly, what would be the easiest way of getting around this?

Upvotes: 0

Views: 75

Answers (1)

Luca Kiebel
Luca Kiebel

Reputation: 10096

You can do this with the assignment operators += and -=.

This is the same as writing variable = variable + change or variable = variable - change 

const currentAccount = [{
    name: 'J.Edge',
    balance: 100,

}];

const withdraw = (amount) => {
    currentAccount[0].balance -= amount
}

const deposit = (amount) => {
    currentAccount[0].balance += amount
}

withdraw(20); // => 100 - 20
deposit(45); // => 80 + 45

console.log(currentAccount[0].balance); // => 125

Note that currentAccount is an Array, thus you need to access an element in there before changing values.

Upvotes: 1

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