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Underscore.js _.negate() Function

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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=
    </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=
    </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>


Output:

false
 true

Reference: https://underscorejs.org/#negate



Last Updated : 25 Nov, 2021
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