Underscore.js is a JavaScript library that provides a lot of useful functions that help in the programming in a big way like the map, filter, invoke, etc even without using any built-in objects.
The _.negate() function is an inbuilt function in Underscore.js library of JavaScript which is used to find a new negated version of the stated predicate function.
Syntax:
_.negate(predicate)
Parameters: It accepts a single parameters which is specified below:
- predicate: It is the stated predicate function.
Return Value: This method returns a new negated version of the stated predicate function.
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>
var isNaN = _.negate(Boolean);
console.log(_.find(
[3, -11, undefined, 41, 0], isNaN));
</script>
</body>
</html>
Output:
undefined
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>
function isCSportal(character) {
return character === "GeeksforGeeks";
}
var isNotCSportal = _.negate(isCSportal);
console.log(isNotCSportal("GeeksforGeeks"));
console.log(isNotCSportal("GfG"));
</script>
</body>
</html>