How to call function on XMLHttpRequest status = true in Vue 2? I get "this.xxxx not a function" error - vue.js

Question

I have the following code, which works fine except for the "makeToast" function that I'm trying to call when status response is true. I get a "this.makeToast is not a function" error on the console.
This function is working fine if I call it after the XMLHttpRequest code. The data is also not being assigned to the msgForm property. I could not figure out why. The "alert(..." message work fine.
<script>
import ToastMixins from '/src/mixins/ToastMixins'
let config = {
headers: {
}
}
export default {
name: 'ModalDestaque',
mixins: [
ToastMixins
],
methods: {
myFunction() {
xhr.onreadystatechange = function () {
if (xhr.readyState === 4) {
console.log('onreadystatechange');
console.log('responseText 1', xhr.responseText);
this.loading = false;
if (xhr.status == 200) {
console.log('responseText 2', xhr.responseText);
let responseObj = JSON.parse(xhr.responseText);
console.log('responseObj', responseObj);
if (responseObj.status == true) {
//alert('Ok');
// this is not working:
this.msgForm = "Message success!";
this.makeToast('b-toaster-bottom-right', true, 'success');
} else {
alert('Not ok...');
}
}
}
};
}
}
}
What am I doing wrong?

Answer 1

I've found the solution while reading the docs at W3 Schools.
W3 Schools AJAX XMLHttp - Multiple Callback Functions
Although, I haven't found a working example anywhere.
In my code, at the button click event that triggers the XMLHttpRequest, I've added the function name "callToast" as a variable, so:
#click="onClickSubmit(myValue, myId, myTitle, callToast)"
Then in the script:
<script>
onClickSubmit(amount, id, title, cFunction) {
// stuff
if (xhr.status == 200) {
let responseObj = JSON.parse(xhr.responseText);
if (responseObj.status == true) {
// here I call the callToast function:
cFunction(this);
alert('Ok');
} else {
alert('Not ok...');
}
}
},
callToast() {
this.msgForm = "Message success!";
this.makeToast('b-toaster-bottom-right', true, 'success');
}
</script>