JavaScript: Build an array, using an iterator function and an initial seed value

JavaScript fundamental (ES6 Syntax): Exercise-111 with Solution

Write a JavaScript program to build  an array, using an iterator function and an initial seed value.

• Use a while loop and Array.prototype.push() to call the function repeatedly until it returns false.
• The iterator function accepts one argument (seed) and must always return an array with two elements ([value, nextSeed]) or false to terminate.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const unfold = (fn, seed) => {
  let result = [],
    val = [null, seed];
  while ((val = fn(val[1]))) result.push(val[0]);
  return result;
};
var f = n => (n > 50 ? false : [-n, n + 10]);
console.log(unfold(f, 10));

Sample Output:

[-10,-20,-30,-40,-50]

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-111-1 by w3resource (@w3resource) on CodePen.

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