Underscore.js is a JavaScript library that makes operations on arrays, string, objects much easier and handy. The _.noop() function is used to return "undefined" irrespective of the arguments passed to it.
Note: It is very necessary to link the underscore CDN before going and using underscore functions in the browser. When linking the underscore.js CDN The "_" is attached to the browser as global variable.
Syntax:
_.noop();
Parameters: It takes optional parameter of any type.
Return Value: This function returns the value of type undefined.
Example 1:
<!DOCTYPE html>
<html>
<head>
<script src=
"https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.9.1/underscore-min.js">
</script>
</head>
<body>
<script>
let str = new String(_.noop())
console.log(`String is ${str}`)
let obj = new Object(_.noop())
console.log(`Object is ${obj.Object}`)
let int = _.noop()
console.log(`Integer is ${int}`)
let arr = new Array(_.noop())
console.log(`Array is ${arr[0]}`)
</script>
</body>
</html>
Output:
Example 2:
<!DOCTYPE html>
<html>
<head>
<script src=
"https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.9.1/underscore-min.js">
</script>
</head>
<body>
<script>
let val = undefined;
let val2 = _.noop();
console.log(val === val2)
if (val == val2)
console.log(
`val and val2 are equal`);
else
console.log(
`val and val2 are not equal`);
</script>
</body>
</html>
Output:
Example 3: Passing parameters to the _.noop() function.
<!DOCTYPE html>
<html>
<head>
<script src=
"https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.9.1/underscore-min.js">
</script>
</head>
<body>
<script>
let func = (para1) => {
console.log(para1)
}
console.log("output: ")
func(_.noop("some value"));
// Pass function as parameter
console.log("output: ")
console.log(_.noop(func))
console.log("output: ")
console.log(_.noop(func()))
</script>
</body>
</html>
Output:
