Variable changed in parent but is not changed in child VueJs - vue.js

Question

I try to change a Boolean variable isSubmited after a post request is made from parent component, and this will trigger a watch from child and there will be another post request that uses the ID form first response.
The flow begins from parent component.
User click on submit
In parent I create a new contract and I receive an ID from response (after post request is made)
After post request, I change a Boolean value ,to activate a watch from child.
In child component I will do another post that uses the ID form parent response
Basically 2 post request, first in parent and the second one in child that uses the ID from parent.
From parent component
<upload-file-test :id_contract="id_contract" :isSubmited="isSubmited" ></upload-file-test>
addContract(data) {
this.isSubmited = !this.isSubmited; //from here in child component watch it works
post("/url", data)
.then((response) => {
this.id_contract = response.data;
this.isSubmited = !this.isSubmited; //from here in child component is not changed
}
}
From child component
props: ['id_contract', 'isSubmited']
watch:{
isSubmited: {
handler(){
console.log('Submited');
//here will be a method for post request
}
},
}

Answer 1

As you can see in the example below the fact that changing a variable in a promise trigger correctly the watcher.
I think that that your post is failing and thus not actually changing isSubmited.
You should catch the error.
post("/url", data).then(response => {
this.id_contract = response.data;
this.isSubmited = !this.isSubmited;
}).catch(error => {
console.log("post is failing")
});
Vue.config.devtools = false;
Vue.config.productionTip = false;
var app = new Vue({
el: '#app',
data: {
bool: false
},
methods: {
test() {
this.bool = !this.bool;
fetch("https://jsonplaceholder.typicode.com/todos/1").then(() => {
this.bool = !this.bool;
});
}
},
watch: {
bool: {
handler() {
console.log("CHANGE");
}
}
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app">
<button #click="test">test</button>
</div>