If have a situation where I want to setup my 'reactivity' programatically, at run time.
I want a function like: dependsOn(dataValName, someOtherDataVal) where if someOtherDataVal changes, then dataValName is updated. e.g. dependsOn('a', 'b') if the value of b changes, then a is re-displayed/updated.
Does such a function exist?
Your question is vague, but what you probably need is a computed property. Vue will automatically detect the dependencies of computed properties. For example, there is no need to be explicit here:
new Vue({
data() {
return {
firstName: 'John',
lastName: 'Doe',
}
},
computed: {
fullName() {
return `${ firstName } ${ lastName }`;
}
}
})
Any time firstName or lastName changes, the computed property fullName will also be re-evaluated.
Sounds like you're talking about watchers. For example
data: () => ({
dataValName: 'a',
someOtherDataVal: 'b'
}),
watch: {
someOtherDataVal (newValue) {
this.dataValName = 'c' // or whatever
}
}
Keep in mind, computed properties are almost always a better option.
