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JavaScript: Combine the numbers of a given array into an array containing all combinations

JavaScript fundamental (ES6 Syntax): Exercise-9 with Solution

Write a JavaScript program to combine the numbers of a given array into an array containing all combinations.

  • Use Array.prototype.reduce() combined with Array.prototype.map() to iterate over elements and combine into an array containing all combinations.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const powerset = arr => arr.reduce((a, v) => a.concat(a.map(r => [v].concat(r))), [[]]);
console.log(powerset([1, 2]));
console.log(powerset([1, 2, 3]));
console.log(powerset([1, 2, 3, 4]));

Sample Output:

[[],[1],[2],[2,1]]
[[],[1],[2],[2,1],[3],[3,1],[3,2],[3,2,1]]
[[],[1],[2],[2,1],[3],[3,1],[3,2],[3,2,1],[4],[4,1],[4,2],[4,2,1],[4,3],[4,3,1],[4,3,2],[4,3,2,1]]

Pictorial Presentation:

JavaScript Fundamental: Combine the numbers of a given array into an array containing all combinations

Flowchart:

flowchart: Combine the numbers of a given array into an array containing all combinations

Live Demo:

See the Pen javascript-basic-exercise-1-9 by w3resource (@w3resource) on CodePen.


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Previous: Write a JavaScript program to filter out the specified values from an specified array. Return the original array without the filtered values.
Next: Write a JavaScript program to extract out the values at the specified indexes from an specified array.

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