1// JS Tip of the Day
2// Set an object read only property
3
4const hero = {
5  weapon: 'Batarang'
6};
7
8Object.defineProperty(hero, 'name', {
9  value: 'Batman',
10  writable: false
11});
12
13hero.name = 'Superman'; // Error on strict mode!
14console.log(hero.name); // Batman

1// JS Tip of the Day
2// Get an Object Property Descriptor
3
4const hero = {
5  name: 'Batman',
6  weapon: 'Batarang'
7};
8
9const heroPropertyDescriptor = Object.getOwnPropertyDescriptor(hero, 'name');
10
11console.log(heroPropertyDescriptor); 
12// { value: "Batman", writable: true, enumerable: true, configurable: true }
13// NB Mutating it has no effect on the original property's configuration.

1// JS Tip of the Day
2// Watch the current position of the device with Geolocation API
3
4let geoWatcher;
5const geoTarget = { lat: 37.869186, long: 41.275438 };
6const options = { enableHighAccuracy: true, timeout: 2000, maximumAge: 0 };
7
8function success({ coords }) {
9  if (geoTarget.lat === coords.latitude.toFixed(6) 
10      && geoTarget.long === coords.longitude.toFixed(6)) {
11   	
12  	console.log(`I'Batman! :D`);
13    navigator.geolocation.clearWatch(geoWatcher);
14  }
15}
16
17function error(err) {
18  console.warn(`Error: ${err.code} - ${err.message}`);
19}
20
21if (window.navigator && window.navigator.geolocation) {
22  geoWatcher = navigator.geolocation.watchPosition(success, error, options);
23}

1// JS Tip of the Day
2// Create a range helper with Symbol.iterator
3
4let range = (from = 0, to = 5) => ({
5    from,
6    to,
7
8    [Symbol.iterator]() {
9        this.current = this.from;
10        return this;
11    },
12
13    next() {
14        if (this.current <= this.to) {
15            return { done: false, value: this.current++ };
16        } else {
17            return { done: true };
18        }
19    }
20});
21
22for (const item of range(10, 15)) {
23    console.log(item); // 10, 11, 12, 13, 14, 15
24}

1// JS Tip of the Day
2// Get the current position of the device with Geolocation API
3
4const options = { enableHighAccuracy: true, timeout: 2000, maximumAge: 0 };
5
6function success({ coords }) {
7  console.log(`
8  	Lat: ${coords.latitude}
9    Long: ${coords.longitude}
10    Accuracy (meters): ${coords.accuracy}`
11  );
12}
13
14function error(err) {
15  console.warn(`Error: ${err.code} - ${err.message}`);
16}
17
18if (window.navigator && window.navigator.geolocation) {
19	navigator.geolocation.getCurrentPosition(success, error, options);
20}