/* eslint-disable complexity */
/**
 * @fileoverview Returns the first index at which a given element can be found in the array.
 * @author NHN FE Development Lab <dl_javascript@nhn.com>
 */

'use strict';

var isArray = require('../type/isArray');

/**
 * @module array
 */

/**
 * Returns the first index at which a given element can be found in the array
 * from start index(default 0), or -1 if it is not present.
 * It compares searchElement to elements of the Array using strict equality
 * (the same method used by the ===, or triple-equals, operator).
 * @param {*} searchElement Element to locate in the array
 * @param {Array} array Array that will be traversed.
 * @param {number} startIndex Start index in array for searching (default 0)
 * @returns {number} the First index at which a given element, or -1 if it is not present
 * @memberof module:array
 * @example
 * // ES6
 * import inArray from 'tui-code-snippet/array/inArray';
 * 
 * // CommonJS
 * const inArray = require('tui-code-snippet/array/inArray');
 *
 * const arr = ['one', 'two', 'three', 'four'];
 * const idx1 = inArray('one', arr, 3); // -1
 * const idx2 = inArray('one', arr); // 0
 */
function inArray(searchElement, array, startIndex) {
  var i;
  var length;
  startIndex = startIndex || 0;

  if (!isArray(array)) {
    return -1;
  }

  if (Array.prototype.indexOf) {
    return Array.prototype.indexOf.call(array, searchElement, startIndex);
  }

  length = array.length;
  for (i = startIndex; startIndex >= 0 && i < length; i += 1) {
    if (array[i] === searchElement) {
      return i;
    }
  }

  return -1;
}

module.exports = inArray;