如何从 Javascript 中任何图像类型的 base64 字符串中去除 data:image 部分
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How can I strip the data:image part from a base64 string of any image type in Javascript
提问by Sergio Domínguez
I am currently doing the following to decode base64 images in Javascript:
我目前正在执行以下操作以在 Javascript 中解码 base64 图像：
var strImage = "";
strImage = strToReplace.replace("data:image/jpeg;base64,", "");
strImage = strToReplace.replace("data:image/png;base64,", "");
strImage = strToReplace.replace("data:image/gif;base64,", "");
strImage = strToReplace.replace("data:image/bmp;base64,", "");
As you can see above we are accepting the four most standard image types (jpeg, png, gif, bmp);
正如您在上面看到的，我们接受四种最标准的图像类型（jpeg、png、gif、bmp）；
However, some of these images are very large and scanning through each one 4-5 times with replace seems a dreadful waste and terribly inefficient.
然而，这些图像中的一些非常大，使用替换扫描每个图像 4-5 次似乎是一种可怕的浪费并且非常低效。
Is there a way I could reliably strip the data:image part of a base64 image string in a single pass?
有没有一种方法可以在一次通过中可靠地去除 base64 图像字符串的 data:image 部分？
Perhaps by detecting the first comma in the string?
也许通过检测字符串中的第一个逗号？
Thanks in advance.
提前致谢。
回答by Nicolò
You can use a regular expression:
您可以使用正则表达式：
var strImage = strToReplace.replace(/^data:image\/[a-z]+;base64,/, "");
^means At the start of the stringdata:imagemeans data:image\/means /[a-z]+means One or more characters between a and z;base64,means ;base64,
^表示在字符串的开头data:image表示数据：图像\/表示/[a-z]+表示a 和 z 之间的一个或多个字符;base64,意思是;base64,
回答by Jonas Wilms
var solution = string.split("base64,")[1];
Splits the variable string at "base64," than take the second part.
在“base64”处拆分变量字符串，而不是采用第二部分。
回答by Adrita Sharma
This worked for me :
这对我有用：
var strImage = strToReplace.split(',')[1];
回答by Daan van Hulst
I came across this question looking for a way to strip any header. So just wanted to share this:
我遇到了这个问题，正在寻找一种去除任何标题的方法。所以只想分享这个：
Regex.Replace(strToReplace, @"^.+?(;base64),", string.Empty))
Got this from an excellent answerwhich describes how to:
从一个很好的答案中得到了这个，它描述了如何：
Match any characters as few as possible until a "abc" is found, without counting the "abc".
尽可能少地匹配任何字符，直到找到“abc”，而不计算“abc”。
回答by karzan osman
use this regex
使用这个正则表达式
/[data:image\/[a-z]*;[a-z0-9]*,.*]/gm
