How to add object into an array javascript

Question

I'm trying to add an object to the expense array using the addExpense method.

const account = {
    expenses: [],
    addExpense: function(description, amount){
        let addObject = {
            description : amount
        }
        this.expenses.push(addObject)
    }
}

account.addExpense('Shopping', 50)
console.log(account.expenses)

I get no errors but the result gives me an object using the parameter name and not the actual string value, 'Shopping'. The amount argument works fine.

[{"description": 50}]

Ori Drori · Accepted Answer · 2018-04-30 18:03:22Z

1

Use computed property names - an expression in brackets that evaluates to the key name (the description value in this case):

let addObject = {
    [description] : amount
}

Demo:

const account = {
    expenses: [],
    addExpense: function(description, amount){
        let addObject = {
            [description] : amount
        }
        this.expenses.push(addObject)
    }
}

account.addExpense('Shopping', 50)
console.log(account.expenses)

answered Apr 30, 2018 at 18:03

Ori Drori

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Comments

mhodges · Accepted Answer · 2018-04-30 18:03:57Z

0

Right now, you are setting the "description" property statically. You want a computed property name, like so:

let addObject = {
   [description] : amount
}

Full Example:

const account = {
    expenses: [],
    addExpense: function(description, amount){
        let addObject = {
            [description] : amount
        }
        this.expenses.push(addObject)
    }
}

account.addExpense('Shopping', 50)
console.log(account.expenses)

answered Apr 30, 2018 at 18:03

mhodges

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Comments

z0r0 · Accepted Answer · 2018-04-30 18:17:27Z

0

let account = {
    expenses: [],
    addExpense: function(description, amount){
        let addObject = {};
        addObject[description] = amount
        this.expenses.push(addObject)
    }
}

account.addExpense('Shopping', 50)
console.log(account.expenses)

edited Apr 30, 2018 at 18:17

answered Apr 30, 2018 at 18:13

z0r0

6664 silver badges15 bronze badges

1 Comment

mhodges Over a year ago

const =/= immutability. const merely says that the variable may not be reassigned, it has nothing to do with the value (in regards to object types).

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