JavaScript Cannot set property of undefined

Question

I'm a novice backend developer and I've been tasked with adding some react features and I'm totally out of my depth. The following code generates the exception "Cannot set property '1' of undefined". The first element is id:1 and name:"". I don't think the empty string has anything to do with my problem though since I've tried hardcoding a string and I get the same exception.

payment_code: {
    label: 'Payment Code',
    value: 'payment_code',
    choices: adminSalesStore.paymentCodes.map((payment_code) => {
        console.log(payment_code);
        console.log(payment_code['id']);
        console.log(payment_code['name']);
        displayChoices.payment_code[payment_code['id']] = payment_code['name'];
        return {
            label: payment_code['id'],
            value: payment_code['name']
        }
    }),
    type: 'choice'
},

I really don't understand the error because payment_code['id'] and payment_code['name'] are not null or undefined. The log statements confirm this. Sorry about the super basic question but I've googled the issue pretty extensively and this error still makes absolutely no sense. There's similar functions in the same class and they all work. However, the other methods use const arrays and I need to pull my values from the db.

I think displayChoices.payment_code is what is actually undefined, just below your logs — Meroje
– Meroje, Commented Jul 15, 2016 at 20:03

Barmar · Accepted Answer · 2016-07-15 21:07:35Z

I'm guessing that the property you show is part of the assignment to displayChoices, i.e. it's something like:

displayChoices = {
    ...
    payment_code: {
        label: "Payment Code",
        value: 'payment_code',
        choices: adminSalesStore.paymentCodes.map((payment_code) => {
            console.log(payment_code);
            console.log(payment_code['id']);
            console.log(payment_code['name']);
            displayChoices.payment_code[payment_code['id']] = payment_code['name'];
            return {
                label: payment_code['id'],
                value: payment_code['name']
            }
        }),
        type: 'choice'
    },
    ...
};

The problem is that until this statement finishes, there's no displayChoices.payment_code property, so you can't assign to displayChoices.payment_code[anything].

You should do that assignment after you finish the first assignment.

displayChoices = {
    ...
    payment_code: {
        label: "Payment Code",
        value: 'payment_code',
        type: 'choice'
    },
    ...
};

displayChoices.choices = adminSalesStore.paymentCodes.map((payment_code) => {
    console.log(payment_code);
    console.log(payment_code['id']);
    console.log(payment_code['name']);
    displayChoices.payment_code[payment_code['id']] = payment_code['name'];
    return {
        label: payment_code['id'],
        value: payment_code['name']
    }
}),

RTS · Accepted Answer · 2016-07-15 20:21:37Z

0

It looks like it's displayChoices.payment_code that is undefined. displayChoices is defined, or it would be complaining about setting the payment code for that, so I would define displayChoices.payment_code = [] or {} (depending on what you're going for) before running this block of code. Or possibly you're looking for displayChoices.paymentCodes, which would be more like your previous choice of adminSalesStore.paymentCodes, and would make more sense to me. Not sure without seeing more of your code.

answered Jul 15, 2016 at 20:21

RTS

9605 silver badges6 bronze badges

Collectives™ on Stack Overflow

JavaScript Cannot set property of undefined

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related