If you want to use watch to observe your property, you could call your method it with this.foo:
data: function () {
return {
questions: []
}
},
watch: {
questions: {
handler: function(val, oldVal) {
this.foo(); // call it in the context of your component object
},
deep: true
}
},
methods: {
foo() {
console.log("foo called");
}
}
To answer your question about handler: It is a keyword property that can take either a function expression (as in the example) or a reference to a function, such as:
function myHandler() { ... } // Defined somewhere outside of the vue component object
...
handler: myHandler,
...
Just out of curiosity: Do you need to watch a property in order to do something every time it changes or could computed properties solve your problem as well?