Array flatten

gistfile1.txt

// For browser not complete support ES6, should transpile to ES5 using Babel

function flatten(input, output = []) {
  if (Array.isArray(input)) {
    input.forEach(ele => {
      if (Array.isArray(ele)) {
        flatten(ele, output)
      } else {
        output.push(ele)
      }
    })
  }
  return output
}


// Test helper
function equalArray(arr1, arr2) {
  if (arr1.length === arr2.length) {
    for (let i = 0; i < arr1.length; i ++) {
      if (arr1[i] !== arr2[i]) {
        return false
      }
    }
    return true
  }
  return false
}

// Test
console.log(equalArray(flatten([[1, 2, [3]], 4]), [1, 2, 3, 4]))
console.log(equalArray(flatten([1, 2, [[]]]), [1, 2]))
const a = { foo: 3 }, b = { bar: 4 }
console.log(equalArray(flatten([1, [a], b]), [1, a, b]))