https://github.com/slavahatnuke/iobserver
https://github.com/slavahatnuke/iobserver
Last synced: 2 months ago
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- Host: GitHub
- URL: https://github.com/slavahatnuke/iobserver
- Owner: slavahatnuke
- Created: 2017-04-03T18:23:02.000Z (about 8 years ago)
- Default Branch: master
- Last Pushed: 2017-04-15T00:44:11.000Z (about 8 years ago)
- Last Synced: 2025-03-03T01:08:16.976Z (3 months ago)
- Language: JavaScript
- Size: 14.6 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# iobserver
It's classical Observer pattern for any object.
## Example
```javascript
let user = {
name: 'slava',
counter: 0
};
// mark it as observable
observable(user);
assert.deepEqual(user, {
name: 'slava',
counter: 0
});
let onNotify = (payload) => user.counter+=payload; // this is just for example, but will be called on notify
subscribe(user, onNotify);
assert.equal(user.counter, 0);
// lets notify, it should inc call onNotify
notify(user, 5);
// yep counter updated
assert.equal(user.counter, 5);
// once again
notify(user, 1);
// updated
assert.equal(user.counter, 6);
// ok, lets unsubscribe, it should not receive calls now
unsubscribe(user, onNotify);
// fire
notify(user, 1);
//nothing changed
assert.equal(user.counter, 6);
// once again
notify(user, 'it should not update');
//nothing
assert.equal(user.counter, 6);
```
## Spec
```javascript
const assert = require('assert');
const {observable, subscribe, unsubscribe, notify, update} = require('iobserver');
describe('iobserver', () => {
it('subscribe/unsubscribe/notify', () => {
let user = {
name: 'slava',
counter: 0
};
// mark it as observable
observable(user);
assert.deepEqual(user, {
name: 'slava'
});
let onNotify = (value) => user.counter++; // this is just for example, but will be called on notify
subscribe(user, onNotify);
assert.equal(user.counter, 0);
// lets notify, it should inc call onNotify
notify(user, 5);
// yep counter updated
assert.equal(user.counter, 5);
// once again
notify(user, 1);
// updated
assert.equal(user.counter, 6);
// ok, lets unsubscribe, it should not receive calls now
unsubscribe(user, onNotify);
// fire
notify(user, 1);
//nothing changed
assert.equal(user.counter, 6);
// once again
notify(user, 'it should not update');
//nothing
assert.equal(user.counter, 6);
});
it('subscribe/update sync', () => {
let state = observable({
name: 'slava'
});
let name = null;
let iCounter = 0;
let detector = (state) => {
name = state.name;
iCounter++;
};
subscribe(state, detector);
assert.equal(iCounter, 0);
assert.equal(name, null);
return update(state, (state) => {
state.name = 'eugene';
}).then(() => {
assert.equal(name, 'eugene');
assert.equal(iCounter, 1);
});
});
it('subscribe/update async', () => {
let state = observable({
name: 'slava'
});
let name = null;
let iCounter = 0;
let detector = (state) => {
name = state.name;
iCounter++;
};
subscribe(state, detector);
assert.equal(iCounter, 0);
assert.equal(name, null);
return update(state, (state) => {
let wait = (timeout) => new Promise((resolve) => setTimeout(resolve, timeout));
return Promise.resolve()
.then(() => wait(10)) //do something async, 10ms just for ex.
.then(() => {
state.name = 'eugene';
})
})
.then(() => {
assert.equal(name, 'eugene');
assert.equal(iCounter, 2); // it will be called twice, #1 for sync, #2 for async
});
});
});
```