// uri = file:///data/user/0/host.exp.exponent/cache/ExperienceData/%2540dedicatedmanagers%252Fmy-app/ImagePicker/eb116538-d9ce-4c75-9c51-d5f45b1318f6.jpg
let extension = uri.match(/\..*?$/i);
I’m trying to pull off the file extension from a uri returned by imagePicker. On iOS I get the dot (.) and the extension. The question mark (?) seems to be doing its job of stopping the any character star (*) from being greedy.
// extension = .jpg
However on Android, Its matching from the first dot (.)
This reminds me of the joke: (No offense intended)
Some people, when confronted with a problem, think “I know, I’ll use regular expressions.” Now they have two problems.
This does seem like something weird is going on with the JavaScript engine
Are you using the default JavaScript Core, or Hermes as the JavaScript engine?
This regex doesn’t involve letters, so the “i” flag is unnecessary, but should not be a problem, of course.
You could avoid the greedy operator by using this regular expression instead:
let extension = uri.match(/\.[^.]*$/);
although you might want to be a bit more restrictive of the characters you accept in the extension.
By the way, how are you logging the extension? uri.match() should return an array. Not a string.
You could avoid the regex entirely if you don’t care what characters the extension contains like this:
I ended up switching to the expression below, but I like your lastIndexOf way better so I’ll be using it!:
uri.match(/\.\w\w\w?$/i);
Note that in order to get the period I had to remove the +1 (granted I didn’t specify that in my question)
const extension = uri.slice(uri.lastIndexOf('.') ); // includes the period in the extension
How do I know if I’m using the default JavaScript Core, or Hermes as the JavaScript engine? I used the expo cli to create the project so I’d bet I’m using the default. I’m testing in the Expo Go app.
Finally, I am pulling the 0th index off of the regex match to get the extension (I didn’t show it in my question). And, because I use the end of string operator ($) in my regex, it should always only return an array with 1 match/value, if one is found.
I’m glad you like it. Just bear in mind that str.lastIndexOf('.') will return -1 if there is no ., and str.slice(-1) will return the last character of the string. So you might want to check if the index is >= 0 before using it.
