How to implement methods and state for vue.js component - vue.js

Question

I'm a beginner in VueJS. And as part of my learning process, I'm building a knob for my Pomodoro app. This is my fiddle.
I copied the knob code from codepen, which is implemented using jquery. As you can see in the fiddle most of the job is done by jquery.
I need to try and do this using Vue.js, using its methods and states.
How to refactor this code to a better Vue.JS code? Any suggestions much appreciated.
Vue.component('timer', {
mounted() {
var knob = $('.knob');
var angle = 0;
var minangle = 0;
var maxangle = 270;
var xDirection = "";
var yDirection = "";
var oldX = 0;
var oldY = 0;
function moveKnob(direction) {
if(direction == 'up') {
if((angle + 2) <= maxangle) {
angle = angle + 2;
setAngle();
}
}
else if(direction == 'down') {
if((angle - 2) >= minangle) {
angle = angle - 2;
setAngle();
}
}
}
function setAngle() {
// rotate knob
knob.css({
'-moz-transform':'rotate('+angle+'deg)',
'-webkit-transform':'rotate('+angle+'deg)',
'-o-transform':'rotate('+angle+'deg)',
'-ms-transform':'rotate('+angle+'deg)',
'transform':'rotate('+angle+'deg)'
});
// highlight ticks
var activeTicks = (Math.round(angle / 10) + 1);
$('.tick').removeClass('activetick');
$('.tick').slice(0,activeTicks).addClass('activetick');
// update % value in text
var pc = Math.round((angle/270)*100);
$('.current-value').text(pc+'%');
}
var RAD2DEG = 180 / Math.PI;
knob.centerX = knob.offset().left + knob.width()/2;
knob.centerY = knob.offset().top + knob.height()/2;
var offset, dragging=false;
knob.mousedown(function(e) {
dragging = true;
offset = Math.atan2(knob.centerY - e.pageY, e.pageX - knob.centerX);
})
$(document).mouseup(function() {
dragging = false
})
$(document).mousemove(function(e) {
if (dragging) {
if (oldX < e.pageX) {
xDirection = "right";
} else {
xDirection = "left";
}
oldX = e.pageX;
if(xDirection === "left") {
moveKnob('down');
} else {
moveKnob('up');
}
return false;
}
})
}
});

Answer 1

This example runs without jQuery.
https://jsfiddle.net/guanzo/d6vashmu/6/
Declare all the variables you need in the data function.
Declare all functions under the methods property.
Declare variables that are derived from other variables in the computed property, such as knobStyle, activeTicks, and currentValue, which are all computed from angle. Whenever angle changes, these 3 computed properties will automatically update.
Regarding the general usage of Vue, you should focus on manipulating the data, and letting Vue update the DOM for you.