jQuery inArray how to use it right

Question

First time I work with jQuery inArray   and it acts kinda strange   If the object is in the array  it will return 0  but 0 is false in Javascript  So the following will output   is NOT in array   var myarray       myarray push  test     if jQuery inArray  test   myarray         console log  is in array      else       console log  is NOT in array        I will have to change the if statement to   if jQuery inArray  test   myarray   0    But this makes the code unreadable  Especially for someone who doesn t know this function  They will expect that jQuery inArray  test   myarray  gives true when  test  is in the array   So my question is  why is it done this way  I realy dislike this  But there must be a good reason to do it like that

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User · Answer

inArray   does the EXACT SAME THING as myarray indexOf   and returns the index of the item you are checking the array for the existence of  It s just compatible with earlier versions of IE before IE9  The best choice is probably to use myarray includes   which returns a boolean true false value  See snippet below for output examples of all 3 methods    x000D   x000D     Declare the array and define it s values x000D  var myarray     Cat    Dog    Fish    x000D   x000D     Display the return value of each jQuery function  x000D     when a radio button is selected x000D     input radio   change  function     x000D   x000D       Get the value of the selected radio x000D    var selectedItem      input radio name arrayItems  checked   val    x000D        item   text  selectedItem    x000D     x000D       Calculate and display the index of the selected item x000D        indexVal   text  myarray indexOf selectedItem     x000D     x000D       Calculate and display the   inArray   value for the selected item x000D        inArrVal   text    inArray selectedItem  myarray     x000D     x000D       Calculate and display the  includes value for the selected item x000D        includeVal   text  myarray includes selectedItem     x000D      x000D   results   line-height  1 8em    x000D   resultLabels   width  14em  display  inline-block  margin-left  10px  float  left    x000D  label   margin-right  1 5em    x000D   space   margin-right  1 5em    x000D   lt script src  https   ajax googleapis com ajax libs jquery 2 1 1 jquery min js  gt  lt  script gt  x000D   x000D  Click a radio button to display the output of x000D   amp nbsp  lt code gt   inArray   lt  code gt  x000D   amp nbsp vs   lt code gt myArray indexOf   lt  code gt  x000D   amp nbsp vs   lt code gt myarray includes   lt  code gt  x000D   amp nbsp when tested against x000D   amp nbsp  lt code gt myarray     Cat    Dog    Fish    lt  code gt  lt br gt  lt br gt  x000D   x000D   lt label gt  lt input type  radio  name  arrayItems  value  Cat  gt  Cat lt  label gt  x000D   lt label gt  lt input type  radio  name  arrayItems  value  Dog  gt  Dog lt  label gt  x000D   lt label gt  lt input type  radio  name  arrayItems  value  Fish  gt  Fish lt  label gt    x000D   lt label gt  lt input type  radio  name  arrayItems  value  N A  gt    Not in Array lt  label gt  x000D   lt br gt  lt br gt  x000D   x000D   lt div id  results  gt  x000D     lt strong gt Results  lt  strong gt  lt br gt  x000D     lt div id  resultLabels  gt  x000D      myarray indexOf    lt span class  item  gt item lt  span gt     lt br gt  x000D        inArray    lt span class  item  gt item lt  span gt    myarray   lt br gt  x000D      myarray includes    lt span class  item  gt item lt  span gt     x000D     lt  div gt  x000D     lt div id  resultOutputs  gt  x000D       lt span class  space  gt   lt  span gt  lt span id  indexVal  gt  lt  span gt  lt br gt  x000D       lt span class  space  gt   lt  span gt  lt span id  inArrVal  gt  lt  span gt  lt br gt  x000D       lt span class  space  gt   lt  span gt  lt span id  includeVal  gt  lt  span gt  x000D     lt  div gt  x000D    lt  div gt  x000D   x000D   x000D

User · Answer

Man  check the doc   for example   var arr     4   Pete   8   John     console log jQuery inArray   John   arr      3

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jQuery inArray   method is use to search a value in an array and return its index not a Boolean value  And if the value was not found it   ll return -1   So  to check if a value is present in an array  follow the below practice   myArray   new Array  php    tutor    if    inArray  php   myArray      -1          alert  found        Reference

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The inArray function returns the index of the object supplied as the first argument to the function in the array supplied as the second argument to the function   When inArray returns 0 it is indicating that the first argument was found at the first position of the supplied array   To use inArray within an if statement use   if jQuery inArray  test   myarray     -1        console log  is in array      else       console log  is NOT in array        inArray returns -1 when the first argument passed to the function is not found in the array passed as the second argument

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Or if you want to get a bit fancy you can use the bitwise not     and logical not    operators to convert the result of the inArray function to a boolean value   if    jQuery inArray  test   myarray         console log  is in array      else       console log  is NOT in array

User · Answer

Just no one use   instead of jQuery   if    inArray nearest node name  array  gt  0      console log  is in array     else     console log  is not in array

User · Answer

It will return the index of the item in the array  If it s not found you will get -1

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inArray returns the index of the element in the array  If the element was not found  -1 will be returned else index of element  if jQuery inArray  quot element quot   myarray      -1        console log  quot Not exists in array quot      else       console log  quot Exists in array quot

User · Answer

The answer comes from the first paragraph of the documentation check if the results is greater than -1  not if it s true or false   The   inArray   method is similar to JavaScript s native  indexOf   method in that it returns -1 when it doesn t find a match  If the first element within the array matches value    inArray   returns 0  Because JavaScript treats 0 as loosely equal to false  i e  0    false  but 0     false   if we re checking for the presence of value within array  we need to check if it s not equal to  or greater than  -1

User · Answer

The right way of using inArray x  arr  is not using it at all  and using instead arr indexOf x    The official standard name is also more clear on the fact that the returned value is an index thus if the element passed is the first one you will get back a 0  that is falsy in Javascript     Note that arr indexOf x  is not supported in Internet Explorer until IE9  so if you need to support IE8 and earlier  this will not work  and the jQuery function is a better alternative

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jQuery inArray   returns index of the item in the array  or -1 if item was not found  Read more here  jQuery inArray

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instead of using jQuery inArray   you can also use includes method for int array    var array1    1  2  3    console log array1 includes 2       expected output  true  var pets     cat    dog    bat     console log pets includes  cat        expected output  true  console log pets includes  at        expected output  false   check official post here

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For some reason when you try to check for a jquery DOM element it won t work properly  So rewriting the function would do the trick   function isObjectInArray array obj       for var i   0  i  lt  array length  i              if   obj  is array i                  return i                      return -1

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inArray returns the index of the element if found or -1 if it isn t -- not a boolean value  So the correct is  if jQuery inArray  test   myarray     -1        console log  is in array      else       console log  is NOT in array

User · Answer

the shortest and simplest way is   arrayHere     cat1    dog2    bat3      if arrayHere any key want to search         console log  yes found in array

User · Answer

I usually use  if   jQuery inArray  test   myarray   lt  0     or  if jQuery inArray  test   myarray   gt   0

User · Answer

inArray returns the index of the element in the array  not a boolean indicating if the item exists in the array  If the element was not found  -1 will be returned   So  to check if an item is in the array  use   if jQuery inArray  test   myarray      -1

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If we want to check an element is inside a set of elements we can do for example   var checkboxes checked      input type  checkbox   checked        Whenever a checkbox or input text is changed    input type  checkbox    input type  text     change function            Checking if the element was an already checked checkbox     if   inArray    this  0   checkboxes checked      -1            alert  this checkbox was already checked

User · Answer

one two tree   i test field     field   Two     true    one two tree   i test field     field   six     false                  ui test field     field           true   This is useful for checking dynamic variables  This method is easy to read

[javascript] jQuery.inArray(), how to use it right?

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