如何从Javascript中任何图像类型的base64字符串中剥离数据:图像部分

2022-01-21 00:00:00 string image base64 javascript

我目前正在执行以下操作以在 Javascript 中解码 base64 图像:

I am currently doing the following to decode base64 images in Javascript:

    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,", "");

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)；

As you can see above we are accepting the four most standard image types (jpeg, png, gif, bmp);

但是，其中一些图像非常大，用替换扫描每张图像 4-5 次似乎是一种可怕的浪费，而且效率极低.

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.

有没有一种方法可以可靠地一次性剥离 base64 图像字符串的 data:image 部分?

Is there a way I could reliably strip the data:image part of a base64 image string in a single pass?

也许通过检测字符串中的第一个逗号?

Perhaps by detecting the first comma in the string?

提前致谢.

推荐答案

可以使用正则表达式:

var strImage = strToReplace.replace(/^data:image/[a-z]+;base64,/, "");

<小时>

  • ^ 表示在字符串的开头
  • data:image 表示 data:image
  • / 表示 /
  • [a-z]+ 表示a和z之间的一个或多个字符
  • ;base64, 表示 ;base64,

    • ^ means At the start of the string
    • data:image means data:image
    • / means /
    • [a-z]+ means One or more characters between a and z
    • ;base64, means ;base64,

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