TypeError: toRaw(...)[key].apply is not a function - Vue.js Debugging Guide

This error typically occurs when trying to call a method on an undefined or null value. The error message 'TypeError: toRaw(...)[key].apply is not a function' suggests that the object being accessed by the toRaw function does not have a method with the name specified by the key variable.

To fix this error, you need to ensure that the object returned by toRaw actually has the method you are trying to call. Double-check the object and the method you are using, and make sure they are defined and accessible at the point of the error.

Additionally, you can use console.log statements or a debugger to inspect the value of toRaw(...)[key] before calling .apply() to see if it is indeed a function or if the object is defined correctly.