Nodejs Array Include includes(searchElement /*, fromIndex*/)

Method Source Code

if (!Array.prototype.includes) {
  Array.prototype.includes = function(searchElement /*, fromIndex*/) {
    'use strict';
    if (this == null) {
      throw new TypeError('Array.prototype.includes called on null or undefined');
    }// ww w  .j  a  va  2  s  .  c  o  m

    var O = Object(this);
    var len = parseInt(O.length, 10) || 0;
    if (len === 0) {
      return false;
    }
    var n = parseInt(arguments[1], 10) || 0;
    var k;
    if (n >= 0) {
      k = n;
    } else {
      k = len + n;
      if (k < 0) {k = 0;}
    }
    var currentElement;
    while (k < len) {
      currentElement = O[k];
      if (searchElement === currentElement ||
         (searchElement !== searchElement && currentElement !== currentElement)) { // NaN !== NaN
        return true;
      }
      k++;
    }
    return false;
  };
}

Related

1. includes(item)

   Array.prototype.includes = function(item) {
       return this.indexOf(item) > -1;
   

2. includes(matcher)

   Array.prototype.includes = function(matcher) {
     var includes = false
       , arr = this;
     for( var j = 0, str; str = arr[j++]; ) {
       if( typeof str === "string" && str.includes(matcher) ) {
         includes = true;
     return includes;
   ...
   

3. includes(s)

   Array.prototype.includes = function(s) {
       return this.indexOf(s) > -1;
   };
   

4. includes(searchElement /*, fromIndex*/ )

   Array.prototype.includes = Array.prototype.includes || (function(searchElement  ) {
     var O = Object(this);
     var len = parseInt(O.length, 10) || 0;
     if (len === 0) return false;
     var n = parseInt(arguments[1], 10) || 0;
     var k;
     if (n >= 0) {
       k = n;
     } else {
   ...
   

5. includes(searchElement /*, fromIndex*/ )

   if (![].includes) {
     Array.prototype.includes = function(searchElement  ) {
       if (this === undefined || this === null) {
         throw new TypeError('Cannot convert this value to object');
       var O = Object(this);
       var len = parseInt(O.length, 10) || 0;
       if (len === 0) {
         return false;
   ...
   

6. includes(searchElement)

   Array.prototype.includes = function(searchElement) {  
       var O = Object(this);
       var len = parseInt(O.length) || 0;
       if (len === 0) {
         return false;
       var n = parseInt(arguments[1]) || 0;
       var k;
       if (n >= 0) {
   ...
   

7. includes(target)

   Array.prototype.includes = function (target) {
     var result = false
     this.forEach(function (el) {
       if (el == target) {
         result = true
     });
     return result;
   

8. includes(target)

   Array.prototype.includes = function(target) {
     for(var i in this) {
       if(this[i] === target) {
         return true;
       };
     };
     return false;
   };
   

9. includes(val)

   Array.prototype.includes = function (val) {
     var returnValue = false;
     this.forEach(function (el, i){
       if (val === el) {
         returnValue = true;
     });
     return returnValue;
   };
   ...