Nodejs Array Last Index lastIndexOf(value, begin, strict)

Method Source Code

/**// w ww.j av a  2s  .c  om
 * insert is a method of Array to get index of the last element that matches value
 *
 * @param value       a Object (String, Number, ...), element to search index
 * @param begin       a Number, index where begin of search
 * @param strict      a Boolean, if search is strict (Optional)
 * @return            a Array, the array with the element inserted;
 */
Array.prototype.lastIndexOf = function(value, begin, strict)
{
  begin = +begin || 0;
  var i = this.length;
  while(i-- > begin)
  {
    if(this[i] === value || strict && this[i] == value )
    {
      return i;
    }
  }
  return -1;
};

Related

1. lastIndexOf(elt /*, from*/)

   Array.prototype.lastIndexOf = Array.prototype.lastIndexOf || function(elt )  {
       var len = this.length;
       var from = Number(arguments[1]);
       if (isNaN(from)) {
           from = len - 1;
       } else {
           from = (from < 0)
               ? Math.ceil(from)
               : Math.floor(from);
   ...
   

2. lastIndexOf(item)

   Array.prototype.lastIndexOf = function(item){
     var lastIndex = -1;
     for (var i=0; i<this.length; i++){
       if (this[i] === item){
         lastIndex = i;
     return lastIndex;
   

3. lastIndexOf(o)

   Array.prototype.lastIndexOf = function (o) {
       var index = this.length;
       for (; index >= 0; index--) {
           if (index in this && this[index] === o)
               return index;
       return -1;
   };
   

4. lastIndexOf(searchElement, fromIndex)

   Array.prototype.lastIndexOf = function(searchElement, fromIndex) {
     if (!fromIndex || !isFinite(fromIndex)) {
       fromIndex = this.length - 1;
     for (var i = fromIndex; i >= 0; --i) {
       if (this.hasOwnProperty(i) && this[i] === searchElement) {
         return i;
     return -1;
   

5. lastIndexOf(v,b)

   Array.prototype.lastIndexOf = function(v,b){
       var idx=-1;
     if(b===true && typeof(v)=="function"){
       for (var i=this.length-1;i>=0;i--) {
         if(v(this[i])){idx=i; break;}
     } else {
       for (var i=this.length-1;i>=0;i--) {
         if(this[i]===v){idx=i; break;}
   ...