JavaScript: Return true if the provided predicate function returns false for all elements in a collection, false otherwise

JavaScript fundamental (ES6 Syntax): Exercise-91 with Solution

All Elements Fail Predicate Check

Write a JavaScript program that returns true if the provided predicate function returns false for all elements in a collection, false otherwise.

• Use Array.prototype.some() to test if any elements in the collection return true based on fn.
• Omit the second argument, fn, to use Boolean as a default.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2
// Define the 'none' function to check if none of the elements in an array satisfy a given condition.
const none = (arr, fn = Boolean) => !arr.some(fn);

// Example usage:
console.log(none([0, 1, 3, 0], x => x == 2));  
console.log(none([0, 0, 0])); //  

Output:

true
true

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-91-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that returns true if a provided predicate function returns false for every element in a collection.
• Write a JavaScript function that iterates over an array and confirms that no element satisfies a given condition.
• Write a JavaScript program that uses Array.every() with the negation of a predicate to determine if all elements fail the test.

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