I need to determine if a value exists in an
array.
I am using the following
function:
Array.prototype.contains
= function(obj) {
var i = this.length;
while (i--)
{
if (this[i] == obj) {
return true;
}
}
return
false;
}
The
above function always returns
false.
The array values and the
function call is as
below:
arrValues = ["Sam","Great",
"Sample",
"High"]
alert(arrValues.contains("Sam"));
Answer
var contains = function(needle)
{
// Per spec, the way to identify NaN is that it is not equal to
itself
var findNaN = needle !== needle;
var
indexOf;
if(!findNaN && typeof
Array.prototype.indexOf === 'function') {
indexOf =
Array.prototype.indexOf;
} else {
indexOf = function(needle)
{
var i = -1, index = -1;
for(i = 0; i <
this.length; i++) {
var item = this[i];
if((findNaN && item !== item) || item === needle) {
index =
i;
break;
}
}
return
index;
};
}
return
indexOf.call(this, needle) >
-1;
};
You
can use it like this:
var myArray
= [0,1,2],
needle = 1,
index = contains.call(myArray, needle); //
true
href="http://codepen.io/anon/pen/mVRNaJ" rel="noreferrer">CodePen
validation/usage
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