Question

Answering How to check if value exist in jQuery .data() function

(Please no downvotes on the validity of adding a bunch of data values to a form object, not my decision)

I created a jsfiddle using each

which gives

Object {v1: "value11", v2: "value2", v3: "value3", v4: "value4", v5: "value5"} fiddle.jshell.net:25
Uncaught TypeError: Object #<Object> has no method 'each'

NOTE: If I wrap the object in $(..) it does not work either

SOLVED USING $.each jsfiddle using $.each

$(function() {
  $("form[name=update]").data("values", {"v1": "value11", "v2": "value2", "v3": "value3", "v4": "value4", "v5": "value5"});
  $(".but").on("click",function(e) {
    var $fData = $("form[name=update]").data("values");
    var val = $(this).val();
      console.log($fData);
    $fData.each(function(n,i) { 
        console.log("!!!",n,i)
      if (n[i]===val) {
        alert("duplicate value");
        return false;
      }    
    })  
    e.preventDefault()  
  });
});  

and

jsfiddle using grep which fails completely at the task.

$(function() {
  $("form[name=update]").data("values", {"v1": "value11", "v2": "value2", "v3": "value3", "v4": "value4", "v5": "value5"});
  $(".but").on("click",function() {
    var $fData = $("form[name=update]").data("values");
    var val = $(this).val();
    var idx = $.grep($fData, function(n,i) { 
        console.log("n",n); // why no console output for this???
        return n[i]===val; 
    });  
    console.log(idx);  
    if (idx!=-1) {
      alert("duplicate value")
    }
  });
});  

Questions:

1. why can’t I run each on the returned object
2. what is up with the grep I am doing (only used grep once before)
3. why is there no console output from inside the grep

Answer 1

$.each is only available to jQuery objects, so you need to wrap your object:

$($fData).each(function (n, i) {

Or pass it to $.each:

$.each($fdata, function(n, i) {

As for $.grep(), the problem is that your input is an object, not an array. $.grep sort of silently fails on you:

grep: function( elems, callback, inv ) {
    var retVal,
        ret = [],
        i = 0,
        length = elems.length;  // <-- Here's why
    inv = !!inv;

    // Go through the array, only saving the items
    // that pass the validator function
    for ( ; i < length; i++ ) {
        retVal = !!callback( elems[ i ], i );
        if ( inv !== retVal ) {
            ret.push( elems[ i ] );
        }
    }

    return ret;
},