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50 changes: 0 additions & 50 deletions locale/en/docs/guides/event-loop-timers-and-nexttick.md
Original file line number Diff line number Diff line change
Expand Up @@ -398,56 +398,6 @@ To get around this, the `'listening'` event is queued in a `nextTick()`
to allow the script to run to completion. This allows the user to set
any event handlers they want.

### Deduplication

For the `timers` and `check` phases, there is a single transition
between C to JavaScript for multiple immediates and timers. This deduplication
is a form of optimization, which may produce some unexpected side effects.
Take this code snippet as an example:

```js
// dedup.js
const foo = [1, 2];
const bar = ['a', 'b'];

foo.forEach(num => {
setImmediate(() => {
console.log('setImmediate', num);
bar.forEach(char => {
process.nextTick(() => {
console.log('process.nextTick', char);
});
});
});
});
```
```bash
$ node dedup.js
setImmediate 1
setImmediate 2
process.nextTick a
process.nextTick b
process.nextTick a
process.nextTick b
```

The main thread adds two `setImmediate()` events, which when processed
will add two `process.nextTick()` events. When the event loop reaches
the `check` phase, it sees that there are currently two events created by
`setImmediate()`. The first event is grabbed and processed, which prints
and adds two events to the `nextTickQueue`.

Because of deduplication, the event loop does not transition back to the
C/C++ layer to check if there are items in the `nextTickQueue` immediately. It
instead continues to process any remaining `setImmediate()` events, of which
one currently remains. After processing this event, two more events are
added to the `nextTickQueue` for a total of four events.

At this point, all previously added `setImmediate()` events have been processed.
The `nextTickQueue` is now checked, and events are processed in FIFO order. When
this `nextTickQueue` is emptied, the event loop considers all operations to have
been completed for the current phase and transitions to the next phase.

## `process.nextTick()` vs `setImmediate()`

We have two calls that are similar as far as users are concerned, but
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