I'm trying to understand how to properly watch for some prop variation. I have a parent component (.vue files) that receive data from an ajax call, put the data inside an object and use it to render some child component through a v-for directive, below is a simplification of my implementation:
<template>
<div>
<player v-for="(item, key, index) in players"
:item="item"
:index="index"
:key="key"">
</player>
</div>
</template>
... then inside the <script>
tag:
data(){
return {
players: {}
},
created(){
let self = this;
this.$http.get('../serv/config/player.php').then((response) => {
let pls = response.body;
for (let p in pls) {
self.$set(self.players, p, pls[p]);
}
});
}
item objects are like this:
item:{
prop: value,
someOtherProp: {
nestedProp: nestedValue,
myArray: [{type: "a", num: 1},{type: "b" num: 6} ...]
},
}
Now, inside my child "player" component I'm trying to watch for any item's property variation and I use:
...
watch:{
'item.someOtherProp'(newVal){
//to work with changes in "myArray"
},
'item.prop'(newVal){
//to work with changes in prop
}
}
It works but it seems a bit tricky to me and I was wondering if this is the right way to do it. My goal is to perform some action every time prop
changes or myArray
gets new elements or there is some variation inside existing ones. Any suggestions will be appreciated.
You can use a deep watcher for that:
watch: {
item: {
handler(val){
// do stuff
},
deep: true
}
}
This will now detect any changes to the objects in the item
array and additions to the array itself (when used with Vue.set). Here's a JSFiddle: http://jsfiddle.net/je2rw3rs/
EDIT
If you don't want to watch for every change on the top level object, and just want a less awkward syntax for watching nested objects directly, you can simply watch a computed
instead:
var vm = new Vue({
el: '#app',
computed: {
foo() {
return this.item.foo;
}
},
watch: {
foo() {
console.log('Foo Changed!');
}
},
data: {
item: {
foo: 'foo'
}
}
})
Here's the JSFiddle: http://jsfiddle.net/oa07r5fw/