Created
March 6, 2017 08:21
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Code to flatten an array of arbitrarily nested arrays of integers into a flat array of integers.
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// NodeJS | |
const assert = require('assert'); | |
/** | |
* Flatten an array of arbitrarily nested arrays of integers into a flat array of integers. | |
* e.g. [[1,2,[3]],4] -> [1,2,3,4]. | |
* | |
* @name flatten | |
* @param {Array} arr An array to flatten, nested or otherwise | |
* @returns {Array} the flattened array | |
* @throws {Error} | |
*/ | |
function flatten(arr) { | |
if (Array.isArray(arr)) { | |
return arr.reduce(function(acc, element) { | |
const items = Array.isArray(element) ? flatten(element) : [element]; | |
return acc.concat(items); | |
}, []); | |
} | |
throw Error('Argument passed is not an array'); | |
} | |
// Tests | |
function testFlatten() { | |
const testCase1 = flatten([[1, 2,], [3, 4], [5, 6]]); | |
const testCase2 = flatten([[1], 2, [3, 4], 5, 6]); | |
const testCase3 = flatten([[1, [2, [3, 4, [5, [6]]]]]]); | |
assert.deepEqual(testCase1, [1,2,3,4,5,6]); | |
assert.deepEqual(testCase2, [1,2,3,4,5,6]); | |
assert.deepEqual(testCase3, [1,2,3,4,5,6]); | |
} | |
testFlatten(); |
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