How to solve the `TypeError: Attempted to assign to readonly property` error

This content originally appeared on flaviocopes.com and was authored by flaviocopes.com

I was doing something in my Next.js codebase when I ran into this problem:

TypeError: Attempted to assign to readonly property

Weird! After a bit of debugging I found the problem. I has nothing to do with Next.js, it can happen in any JavaScript codebase.

I had a column in my database where I stored data as JSON.

In my code I was updating this JSON object, using the dot syntax (like data.name = 'Flavio') but I forgot to call JSON.parse() before doing so.

data was not an object, but a string!

Strings are immutable in JavaScript. We can’t update them once defined. Hence the error. The solution was to, obviously, call JSON.parse() before updating the JSON object.

This content originally appeared on flaviocopes.com and was authored by flaviocopes.com

Print Share Comment Cite Upload Translate Updates

APA

flaviocopes.com | Sciencx (2021-05-12T05:00:00+00:00) How to solve the `TypeError: Attempted to assign to readonly property` error. Retrieved from https://www.scien.cx/2021/05/12/how-to-solve-the-typeerror-attempted-to-assign-to-readonly-property-error/

MLA

" » How to solve the `TypeError: Attempted to assign to readonly property` error." flaviocopes.com | Sciencx - Wednesday May 12, 2021, https://www.scien.cx/2021/05/12/how-to-solve-the-typeerror-attempted-to-assign-to-readonly-property-error/

HARVARD

flaviocopes.com | Sciencx Wednesday May 12, 2021 » How to solve the `TypeError: Attempted to assign to readonly property` error., viewed ,<https://www.scien.cx/2021/05/12/how-to-solve-the-typeerror-attempted-to-assign-to-readonly-property-error/>

VANCOUVER

flaviocopes.com | Sciencx - » How to solve the `TypeError: Attempted to assign to readonly property` error. [Internet]. [Accessed ]. Available from: https://www.scien.cx/2021/05/12/how-to-solve-the-typeerror-attempted-to-assign-to-readonly-property-error/

CHICAGO

" » How to solve the `TypeError: Attempted to assign to readonly property` error." flaviocopes.com | Sciencx - Accessed . https://www.scien.cx/2021/05/12/how-to-solve-the-typeerror-attempted-to-assign-to-readonly-property-error/

IEEE

" » How to solve the `TypeError: Attempted to assign to readonly property` error." flaviocopes.com | Sciencx [Online]. Available: https://www.scien.cx/2021/05/12/how-to-solve-the-typeerror-attempted-to-assign-to-readonly-property-error/. [Accessed: ]

rf:citation

» How to solve the `TypeError: Attempted to assign to readonly property` error | flaviocopes.com | Sciencx | https://www.scien.cx/2021/05/12/how-to-solve-the-typeerror-attempted-to-assign-to-readonly-property-error/ |

Please log in to upload a file.

There are no updates yet.
Click the Upload button above to add an update.

You must be logged in to translate posts. Please log in or register.