Javascript - get extension from base64 image

javascript image base64 file-extension
itsme picture itsme · Jan 11, 2015 · Viewed 53.1k times · Source

I have a base64 encoded image returned from a service and it looks like this:

/9j/4AAQSkZJRgABAQEASABIAAD/4Yp2aHR0cDovL25zLmFkb2JlLmNvbS94YXAvMS4wLwA8P3hwYWNrZXQgYmVnaW49Iu+7vyIgaWQ9Ilc1TTBNcENlaGlIenJlU3pOVGN6a2M5ZCI/Pgo8eDp4bXBtZXRhIHhtbG5zOng9ImFkb2JlOm5zOm1ldGEvIiB4OnhtcHRrPSJBZG9iZSBYTVAgQ29yZSA0LjEtYzAzNiA0Ni4yNzcwOTIsIEZyaSBGZWIgMjMgMjAwNyAxNDoxNjoxOCAgICAgICAgIj4KICAgPHJkZjpSREYgeG1.... etc

How can i detect / check the image extension?

Answer

Up209d picture Up209d · May 1, 2018

A bit late but it seem the question was misunderstood. He just only had the base64 content of the image, not the full data URI.

I wrote here for anyone who encounters with this quest, you can read the first character of content content.charAt(0). By base64 image content if the first char is:

'/' : jpg

'i' : png

'R' : gif

'U' : webp

So for your case, it is 'jpg'.

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