Hi there,
im struggeling with this simple task:
var myAlphas = image.clippingPath.alphaChannelPathNames;
var AlphaIndex = myAlphas.indexOf("our_default");
…because even this example doesnt work:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
var a = fruits.indexOf("Apple");
alert(a);
from JavaScript Array indexOf() Method
All I get is 
and since Im more of a designer than a scripter, i cant solve that by myslef. Someone to the rescue?
1 Correct answer
It's not entirely DBLJan's mistake 
Look here: indexOf Method (Array) (JavaScript) | Microsoft Docs -- it is supported in JavaScript!
But the problem is that InDesign's JavaScript engine is out of date (*). This particular construction did not exist at the time when Adobe implemented it, and nowadays your everyday updated browser properly supports it because they were updated.
(*) It's even so out of date that technically we should not be calling it "JavaScript" at all. The ESTK gets that part r
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17
Replies
It's not entirely DBLJan's mistake 
Look here: indexOf Method (Array) (JavaScript) | Microsoft Docs -- it is supported in JavaScript!
But the problem is that InDesign's JavaScript engine is out of date (*). This particular construction did not exist at the time when Adobe implemented it, and nowadays your everyday updated browser properly supports it because they were updated.
(*) It's even so out of date that technically we should not be calling it "JavaScript" at all. The ESTK gets that part right: it's properly called "ExtendScript".
Phew, i was going mad, why this shouldnt work, …since it was an example direct from the w3school.
Also, as i mentioned, im no trained coder, but I get better at code-snippet-tetris by every script 
As I should have done before I posted this, I haved used the searchforum feature to find this post, suggesting adding this snippet to my code:
Array.prototype.indexOf = function ( item ) {
var index = 0, length = this.length;
for ( ; index < length; index++ ) {
if ( this[index] === item )
return index;
}
return -1;
};
And guess what – it works perfectly. Because after all I only was looking for a way to find something in my array of (…and here I often dont know what im getting, I do best working with strings) values.
But thank you Loic.Aigon for the deep insights!
It boils down for me to use .indexOf to find the index of a value in an array, so ill include the code snippet upon use:
- var fruits = ["orange", "pineapple", "apple", "mango"];
- var a = fruits.toString().indexOf("apple");
- alert(a);
If you forget to switch the ESTK to InDesign and use "ExtendScript Toolkit CC" it will work fine. I assume the current JavaScript-Libary is used.
But if you execute in InDesign it wont "know" of .indexOf and throw an error:
But if you paste the prototype-function mentioned above, its working with InDesign and ESTK CC.
DBLjan wrote
It boils down for me to use .indexOf to find the index of a value in an array, so ill include the code snippet upon use:
var fruits = ["orange", "pineapple", "apple", "mango"]; var a = fruits.toString().indexOf("apple"); alert(a);
If you forget to switch the ESTK to InDesign and use "ExtendScript Toolkit CC" it will work fine.
I assume the current JavaScript-Libary is used.
Hi Jan,
that result is hard to believe. I mean, that the result is actually 2 and not that your snippet is running without error.
Don't know what happened in your case.
Your alert should show 11, because "apple" is already found in "pineapple" and the "a" after "pine" from "pineapple" has index 11 in the string you are building with fruits.toString() which is: "orange,pineapple,apple,mango".
Here my result from your code:
Regards,
Uwe
// EDIT: Added a better looking screenshot.
Others have pointed out that array.indexOf might not have been implemented in Illustrator's ExtendScript. If you want to use this function, you will have to provide it. I'd like to share a good resource for these scripts: MDN, Mozilla's Developer Network.
Mozilla's Developer Network provide polyfills for functions that are not implemented in every browser. This is handy, because it allows us to use the newest JS functions even if they don't exist in ExtendScript. And it's easier then subscribing to yet another forum.
The array.indexOf function has a polyfill as well on: Array.prototype.indexOf() - JavaScript | MDN
Remember to include it at the START of your script, or (more neat) to include it at the top:
Let me paste the code for this Polyfill.
if (!Array.prototype.indexOf) {
Array.prototype.indexOf = function indexOf(member, startFrom) {
/*
In non-strict mode, if the `this` variable is null or undefined, then it is
set to the window object. Otherwise, `this` is automatically converted to an
object. In strict mode, if the `this` variable is null or undefined, a
`TypeError` is thrown.
*/
if (this == null) {
throw new TypeError("Array.prototype.indexOf() - can't convert `" + this + "` to object");
}
var
index = isFinite(startFrom) ? Math.floor(startFrom) : 0,
that = this instanceof Object ? this : new Object(this),
length = isFinite(that.length) ? Math.floor(that.length) : 0;
if (index >= length) {
return -1;
}
if (index < 0) {
index = Math.max(length + index, 0);
}
if (member === undefined) {
/*
Since `member` is undefined, keys that don't exist will have the same
value as `member`, and thus do need to be checked.
*/
do {
if (index in that && that[index] === undefined) {
return index;
}
} while (++index < length);
} else {
do {
if (that[index] === member) {
return index;
}
} while (++index < length);
}
return -1;
};
}
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