times.js 1.68 KB
var bindCallback = require('../internal/bindCallback');

/* Native method references for those with the same name as other `lodash` methods. */
var nativeFloor = Math.floor,
    nativeIsFinite = global.isFinite,
    nativeMin = Math.min;

/** Used as references for the maximum length and index of an array. */
var MAX_ARRAY_LENGTH = 4294967295;

/**
 * Invokes the iteratee function `n` times, returning an array of the results
 * of each invocation. The `iteratee` is bound to `thisArg` and invoked with
 * one argument; (index).
 *
 * @static
 * @memberOf _
 * @category Utility
 * @param {number} n The number of times to invoke `iteratee`.
 * @param {Function} [iteratee=_.identity] The function invoked per iteration.
 * @param {*} [thisArg] The `this` binding of `iteratee`.
 * @returns {Array} Returns the array of results.
 * @example
 *
 * var diceRolls = _.times(3, _.partial(_.random, 1, 6, false));
 * // => [3, 6, 4]
 *
 * _.times(3, function(n) {
 *   mage.castSpell(n);
 * });
 * // => invokes `mage.castSpell(n)` three times with `n` of `0`, `1`, and `2`
 *
 * _.times(3, function(n) {
 *   this.cast(n);
 * }, mage);
 * // => also invokes `mage.castSpell(n)` three times
 */
function times(n, iteratee, thisArg) {
  n = nativeFloor(n);

  // Exit early to avoid a JSC JIT bug in Safari 8
  // where `Array(0)` is treated as `Array(1)`.
  if (n < 1 || !nativeIsFinite(n)) {
    return [];
  }
  var index = -1,
      result = Array(nativeMin(n, MAX_ARRAY_LENGTH));

  iteratee = bindCallback(iteratee, thisArg, 1);
  while (++index < n) {
    if (index < MAX_ARRAY_LENGTH) {
      result[index] = iteratee(index);
    } else {
      iteratee(index);
    }
  }
  return result;
}

module.exports = times;