In this article, we are given a value x, and the task is to check the value against the predicate function. If the value satisfies the condition or predicate return fn(x) else return x.
Predicate functions are the function that takes one item as input and returns true or false based on the whether item satisfies that condition or not.
Example 1: In this example, we have given a number and a condition, if condition is true then it returns the fn(number) otherwise it returns a simple numeric value.
Javascript
<script> // Function that we have to return function fn(x) { let fact = 1; for (i = 1; i <= x; i++) { fact *= i; } return fact; } // Predicate function checking even value function isEven(x) { return (x % 2 === 0); } // Function returning fn(x) if predicate // function return true else return x function test(x) { let e = isEven(x); if (e) { return fn(x); } else return x; } // Printing return value let ans = test(6); console.log(`This function returns ${ans}`); </script> |
Output: Here the condition is a number that should be even because our input data is even so it returns the fn(6) value.
This function returns 720
Example 2: In this example, we have given a number and a test condition, if condition is true then it returns the fn(number) otherwise it returns number value only.
Javascript
<script> // Initializing the max_Integer let max_Integer = 20; // Function we have to return function fn(x) { var b = 0; var a = 1; var sum; for (i = 0; i < x - 1; i++) { sum = a + b; b = a; a = sum; } return a; } // Predicate function checking value // is less than max_Integer function isless(x) { return (x < max_Integer); } // Function return fn(x) if predicate // function return true else return x function test(x) { let e = isless(x); if (e) { return fn(x); } else return x; } // Printing return value let ans = test(15); console.log(`This function returns ${ans}`); </script> |
Output:
The function returns 610
Example 3: In this example, we have given a number and a test condition, if condition is true then it returns the fn(number) otherwise it returns number value only.
Javascript
<script> // Function we have to return function fn(x) { let j = 1; for (i = 0; i < x - 1; i++) { j = j * x; } return j; } // Predicate function checking // multiple of 3 function ismultiple(x) { return (x % 3 == 0); } // Function that returns fn(x) if // predicate function return true // else return false function test(x) { let e = ismultiple(x); if (e) { return fn(x); } else return x; } // Printing value let ans = test(6); console.log(`This function returns ${ans}`); </script> |
Output:
This function returns 7776
