decodeURIComponent mangles path

Question

decodeURIComponent mangles path

When I post the following to node (simplified example):

var xhr = new XMLHttpRequest();
xhr.open("POST", "http://localhost:3000/action");
xhr.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
xhr.send(JSON.stringify({path:encodeURIComponent("E:\foo\bar.baz")}));

node.js code:

app.post('/action', function (request, response) {
    var file = request.body['path'];
    console.log(file);
    console.log(decodeURIComponent(file));
});

I get the following output:

E%3A%0Coo%08ar.baz
E:♀oar.baz

How do I correctly decode this?

javascript
node.js

Answer 1

You are encoding special characters in your path as the backslash is reserved for escaping:

\f Form feed

\b Backspace

When encoded these become:

%0C

%08

From MDN:

To include a literal backslash inside a string, you must escape the backslash character

"E:\\foo\\bar.baz"