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
Write a JavaScript program that will return 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
const none = (arr, fn = Boolean) => !arr.some(fn);
console.log(none([0, 1, 3, 0], x => x == 2));
console.log(none([0, 0, 0]));
Sample Output:
true true
Flowchart:

Live Demo:
See the Pen javascript-basic-exercise-91-1 by w3resource (@w3resource) on CodePen.
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Previous: Write a JavaScript program to nest a given flat array of objects linked to one another recursively.
Next: Write a JavaScript program to create a function that gets the argument at index n. If n is negative, the nth argument from the end is returned.
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JavaScript: Tips of the Day
Chunks an array into n smaller arrays
Example:
const tips_chunkIntoN = (arr, n) => { const size = Math.ceil(arr.length / n); return Array.from({ length: n }, (v, i) => arr.slice(i * size, i * size + size) ); } console.log(tips_chunkIntoN([1, 2, 3, 4, 5, 6, 7,8], 4));
Output:
[[1,2],[3,4],[5,6],[7,8]]
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