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JavaScript: Get a customized coalesce function that returns the first argument that returns true from the provided argument validation function

JavaScript fundamental (ES6 Syntax): Exercise-42 with Solution

Write a JavaScript program to get a customized coalesce function that returns the first argument that returns true from the provided argument validation function.

  • Use Array.prototype.find() to return the first argument that returns true from the provided argument validation function, valid.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const coalesceFactory = valid => (...args) => args.find(valid);
const customCoalesce = coalesceFactory(_ => ![null, undefined, '', NaN].includes(_));
console.log(customCoalesce(undefined, null, NaN, '', 'Waldo'));

Sample Output:

Waldo

Flowchart:

flowchart: Get a customized coalesce function that returns the first argument that returns true from the provided argument validation function

Live Demo:

See the Pen javascript-basic-exercise-1-42 by w3resource (@w3resource) on CodePen.


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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]]