NodeJS globals may be immediately referred to as inside any mission with out importing them. There are lots of built-in globals that present totally different capabilities corresponding to getting the listing title, and file title, printing totally different values within the console, setting timers, exporting and importing modules, and many others. These globals is usually a operate, string, object, and many others.
Completely different Node.js built-in Globals:
- __dirname
- __filename
- console
- course of
- buffer
- setImmediate
- clearImmediate
- setInterval
- clearInterval
- setTimeout
- clearTimeout
- export
- require
__dirname
This world object is used to get the present working listing.
Instance:
console.log("Present Listing is: " + __dirname);
Output:
__filename
This world object is used to get the present working file title path.
Instance:
console.log("Present File Path is: " +__filename);
Output:
console
This world object is used to print various kinds of values within the console.
Instance:
console.log("Whats up World!");
Output:
course of
This world object is used to deal with the at present working processes. The method object offers us with varied strategies corresponding to course of.exit, course of.stdout, course of.stdin, and many others.
Instance:
course of.stdout.write("Whats up World!");
Output:
buffer
This world object is used to deal with streams of binary knowledge.
Instance:
Generally, a personality takes a byte of house, so if we move a string of 5 characters “howdy” the buffer.byteLenght technique will return 5 as output.
const bytes = Buffer.byteLength("howdy");
console.log(bytes);
Output:
setImmediate
This world technique is used to outline a callback operate that runs fast after the execution.
Syntax:
Instance:
const enjoyable = setImmediate(operate() { console.log("Speedy"); });
Right here we outline a callback operate that makes use of the console world object to print a string instantly when the appliance runs.
Output:
clearImmediate
This world technique is used to terminate the execution of the callback operate outlined by the setImmediate technique.
Syntax:
clearImmediate(immediateObject)
Instance:
const enjoyable = setImmediate(operate() { console.log("Speedy"); });
clearImmediate(enjoyable);
The clearImmediate technique will cease the execution of setImmediate so we get nothing as an output.
Output:
setInterval
This world technique is used to outline a callback operate that runs at a particular interval till its termination.
Syntax:
setInterval(callback, delay)
Instance:
setInterval(operate() {
console.log("Operating in interval of 1 millisecond!");
}, 1000);
Right here we outline a callback operate that makes use of the console world object to print a string at an interval of 1 millisecond.
Output:
clearInterval
This world technique is used to cease the execution of the callback operate outlined by the setInterval technique.
Syntax:
clearInterval(intervalObject)
Instance:
var x = 0;
const enjoyable = setInterval(operate() {
x = x + 1;
console.log(x);
if(x == 5) {
clearInterval(enjoyable);
};
}, 1000);
Right here we use the setInterval technique to vary the worth of a variable x and print it and if the worth turns into 5 then the clearInterval technique stops its execution.
Output:
setTimeout
This world technique is used to outline a callback operate that runs after a particular time.
Syntax:
setTimeout(callback, delay)
Instance:
setTimeout(operate() {
console.log("1 millisecond has handed!");
}, 1000);
Right here we outline a callback operate that makes use of the console world object to print a string after 1 millisecond.
Output:
clearTimeout
This world technique is used to cease the execution of the callback operate outlined by the setTimeout technique.
Syntax:
clearTimeout(timeoutObject)
Instance:
var x = true;
const enjoyable = setTimeout(operate() {
console.log("1 millisecond has handed!");
}, 1000);
if(x){
console.log("X is true!");
clearTimeout(enjoyable);
}
Right here we use the setTimeout technique to print a string after 1 millisecond, but when the worth of a variable we outline is true it should cease it so that it’s going to not capable of print the worth after 1 millisecond.
Output:
export
This world object is used to export a module or technique as a way to use it inside one other file.
Instance:
module.exports = "Whats up World!";
We now have a file howdy.js wherein we’re exporting a string in a while we are going to import it utilizing require.
require
That is used to import a module or technique by passing the placement of that module or technique as an argument to this technique.
Instance:
const worth = require("./howdy.js");
console.log(worth);
Right here we’re importing the string export by howdy.js file.
Output:
Abstract
The worldwide object is used to carry out the totally different operations, they will immediately name with out importing them. We hope this tutorial helped you perceive the idea of globals in Node.js.
