this.$set is not function

this.$set is a Vue.js method used to update the value of a property in Vue's reactive data system. It allows you to add or modify a property in an object so that Vue can detect the change and update the UI accordingly.

If you are getting an error message that says "this.$set is not a function", it is likely because you are trying to use it in a context where it is not available.

There are a few possible reasons for this error, such as:

1. You may be trying to use this.$set outside of a Vue component or instance.
2. You may be using an outdated version of Vue that does not include the $set method.
3. You may have a typo in your code, such as writing this.$sets instead of this.$set.

To fix this issue, make sure that you are using this.$set within a Vue component or instance, and that you have included the latest version of Vue. Also, double-check your code for any typos or syntax errors.