nextTick(callback)
is a method provided by the Async module that defers the execution of a function until the next event loop iteration. Similar to how the setTimeout()
is used in browsers to defer execution of a function by a given time, nextTick()
defers execution until the next tick.
In Node.js, each iteration of an event loop is called a tick.
In Node.js, nextTick()
just calls process.nextTick
. In the browser, it will use setImmediate
if available, otherwise it will use setTimeout(callback, 0)
, which means that the other higher priority events may precede the execution of the callback
function.
The function signature is as follows:
nextTick(callback, arg...)
callback
: The function to call on a later loop around the event loopargs...
: (Optional) Additional arguments to pass to the callback
In this example, we simply defer the execution of a function that accepts a name
argument and output that name to the console.
Notice that the statement console.log('1. Hello')
runs before the statement console.log('2.', name)
inside the callback function passed to nextTick()
.
import nextTick from 'async/nextTick';// Defering the execution of a function.nextTick(function(name) {// This will run secondconsole.log('2.', name);}, 'World');// This will run firstconsole.log('1. Hello');
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