This below supposed to alert 'true', but, it is alerting 'No item'. Where i went i wrong on this code. Any clue?
Array.prototype.CheckColor = function (datain) {
for (var i = 0, len = this.length; i < len; i++) {
if (this[i] === datain) {
return true;
} else {
return "No item";
}
}
}
var newstr = "red blue green".split(" ");
var oyrsval = Array.prototype.CheckColor.call(newstr, "blue");
alert(oyrsval);
Should be
Array.prototype.CheckColor = function(datain){
for (var i = 0, len = this.length; i < len;i++ ){
if (this[i] === datain){
return true; // Return true if found
}
}
return "No item"; // else return
}
Or simplier using indexOf:
Array.prototype.CheckColor = function(datain){
return this.indexOf(datain) > -1 ? true : "No item";
}
We it's already explained that your problem is because you return from the loop too early. I will propose another solution, maybe simpler:
Array.prototype.CheckColor = function (datain) {
return this.some(function(el) {
return datain === el;
}) || 'No item';
}
Array.prototype.some method is useful in this case. Also since you are extending prototype there is no need to go hard way with Array.prototype.CheckColor.call(newstr, "blue") when you can directly use newstr.CheckColor("blue").
Check the demo.
Array.prototype.CheckColor = function (datain) {
return this.some(function(el) {
return datain === el;
}) || 'No item';
}
var found = "red blue green".split(" ").CheckColor("blue");
var notfound = "red blues green".split(" ").CheckColor("blue");
alert(found);
alert(notfound);Finally if testing if the item is within array is the only thing you need to do, you can use already available Array.prototype.indexOf method:
newstr.indexOf("blue") !== -1
You are returning the result for the first comparison in your for
Change your code to:
for (var i = 0, len = this.length; i < len;i++) {
if (this[i] === datain) {
return true;
}
}
return "No item";
Change your function to:
Array.prototype.CheckColor = function(datain){
for (var i = 0, len = this.length; i < len;i++ ){
if (this[i] === datain) {
return true;
}
}
// if here, nothing found
return "No item";
}
There's nothing wrong with looping over the array, but you could also regexp directly on the string:
String.prototype.CheckColor = function(datain) {
return RegExp("\\b" + datain + "\\b").test(this);
}
In the real world I suppose you'd want to escape special regexp characters inside datain.
return "No item";outside the for (after)returnoperation after the first element (occurs at both if and else). Maybe the else statement were meant to occur after the loop, if there is nodatainmatch in the object.var oyrsval = newstr.CheckColor("blue');?