Can we use a named function in the Vue3 composition API watcher?

I create a watcher within the setup, this works:

    watch(() => variableToWatch, (newVal,oldVal) => {
        console.log(newVal,oldVal)
    })

But this does not (no errors, just doesn’t seem to do anything):

    const fnTest = (newVal,oldVal) => {
        console.log(newVal,oldVal)
    })

    watch(() => variableToWatch, (newVal,oldVal) => fnTest)

Can we not use a function in the watcher callback?

To be fair, I’m still on Vue3, and use the https://github.com/vuejs/composition-api, but that shoulnd’t matter in this case.

>Solution :

Your const "is" the whole function.

So this should work:

    const fnTest = (newVal,oldVal) => {
        console.log(newVal,oldVal)
    })

    watch(() => variableToWatch, fnTest)