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1/**2 * Mnemonist Iterable Function3 * ============================4 *5 * Harmonized iteration helpers over mixed iterable targets.6 */7var forEach = require('obliterator/foreach');8 9var typed = require('./typed-arrays.js');10 11/**12 * Function used to determine whether the given object supports array-like13 * random access.14 *15 * @param  {any} target - Target object.16 * @return {boolean}17 */18function isArrayLike(target) {19  return Array.isArray(target) || typed.isTypedArray(target);20}21 22/**23 * Function used to guess the length of the structure over which we are going24 * to iterate.25 *26 * @param  {any} target - Target object.27 * @return {number|undefined}28 */29function guessLength(target) {30  if (typeof target.length === 'number')31    return target.length;32 33  if (typeof target.size === 'number')34    return target.size;35 36  return;37}38 39/**40 * Function used to convert an iterable to an array.41 *42 * @param  {any}   target - Iteration target.43 * @return {array}44 */45function toArray(target) {46  var l = guessLength(target);47 48  var array = typeof l === 'number' ? new Array(l) : [];49 50  var i = 0;51 52  // TODO: we could optimize when given target is array like53  forEach(target, function(value) {54    array[i++] = value;55  });56 57  return array;58}59 60/**61 * Same as above but returns a supplementary indices array.62 *63 * @param  {any}   target - Iteration target.64 * @return {array}65 */66function toArrayWithIndices(target) {67  var l = guessLength(target);68 69  var IndexArray = typeof l === 'number' ?70    typed.getPointerArray(l) :71    Array;72 73  var array = typeof l === 'number' ? new Array(l) : [];74  var indices = typeof l === 'number' ? new IndexArray(l) : [];75 76  var i = 0;77 78  // TODO: we could optimize when given target is array like79  forEach(target, function(value) {80    array[i] = value;81    indices[i] = i++;82  });83 84  return [array, indices];85}86 87/**88 * Exporting.89 */90exports.isArrayLike = isArrayLike;91exports.guessLength = guessLength;92exports.toArray = toArray;93exports.toArrayWithIndices = toArrayWithIndices;94