zoom.js

var electronScreen = require('screen');
var webFrame = require('web-frame');

var currentZoomLevel;
var defaultZoomLevel = webFrame.getZoomFactor();

var defaultWidth = 1030;

function getZoomLevel() {
    var zoomFactor = webFrame.getZoomFactor();
    var width = window.innerWidth * zoomFactor;
    var zoom = width / defaultWidth;

    return zoom;
};

function setZoom() {
    var zoom = getZoomLevel();
    if(zoom < 1) {
        webFrame.setZoomFactor(1);
    } else if(zoom > 2) {
        webFrame.setZoomFactor(2);
    } else {
        webFrame.setZoomFactor(zoom);
    }
};

var increaseZoom = function(){
    currentZoomLevel = currentZoomLevel + 0.25;
    webFrame.setZoomFactor(currentZoomLevel);
};

var decreaseZoom = function(){
    currentZoomLevel = currentZoomLevel - 0.25;
    webFrame.setZoomFactor(currentZoomLevel);
};

var defaultZoom = function(){
    currentZoomLevel = defaultZoomLevel;
    webFrame.setZoomFactor(currentZoomLevel);
}

$(window).on('resize', setZoom);