javascript MIME 类型的文件扩展名

File name extension to MIME type

提问by khan

Using only JavaScript and framework like dojo/jQuery...

只使用 JavaScript 和像 dojo/jQuery 这样的框架......

Is there a way to find the Content-Type for a particular file name extension?

有没有办法找到特定文件扩展名的内容类型？

Say if I type in the string "something.pdf", I want to show an alert that says "application/pdf"

假设我输入字符串“something.pdf”，我想显示一个提示“application/pdf”

or "something.html" show "text/html"?

或“something.html”显示“text/html”？

回答by alex

I think you will need to maintain the mappings yourself (you couldXHR a physical file and get it, but I doubt you want to do that)...

我认为您需要自己维护映射（您可以XHR 物理文件并获取它，但我怀疑您是否愿意这样做）...

(function() {

    var extToMimes = {
       'img': 'image/jpeg',
       'png': 'image/png',
       ...
    }

    window.getMimeByExt = function(ext) {
        if (extToMimes.hasOwnProperty(ext)) {
           return extToMimes[ext];
        }
        return false;
    }

})();

jsFiddle.

js小提琴。

This will return falseif it doesn't exist in your mapping. If you like, you could just return the extToMimes[ext], which will give undefinedif it doesn't exist. It also won't accidentally get things up the prototype chain.

false如果它在您的映射中不存在，它将返回。如果你愿意，你可以只返回extToMimes[ext]，undefined如果它不存在，它将给出。它也不会意外地使原型链上升。

There is also the option of accessing it if it is a file input.

如果它是一个文件，也可以选择访问它input。

var mime = $('input[type="file"]').prop('files')[0].file;

Keep in mind the extension to mime type makes no guarantees about the actual file itself; you'd need to parse it server side to determine what kind of file it really is.

请记住，mime 类型的扩展名不能保证实际文件本身；您需要在服务器端解析它以确定它到底是什么类型的文件。

回答by Ahmed elshiekh

you can use node-mime

你可以使用node-mime

<script src="https://wzrd.in/standalone/mime@latest"></script>
<script>
    mime.getType("something.pdf"); // etc.
<script>