From microsoft/vscode#54026

//tsconfig.json

{
    "compilerOptions": {
        "sourceMap": true,
        "sourceRoot": "src/",
        "mapRoot": "build/"
    }
}

./src/hello.ts exists

Actual

I run tsc and get:

hello.js:

console.log("hello world!");
//# sourceMappingURL=/Users/roblou/Downloads/tsTest/build/hello.js.map

hello.map.js:

{"version":3,"file":"hello.js","sourceRoot":"/Users/roblou/Downloads/tsTest/src/","sources":["hello.ts"], ...

Expected

This stuff is not clearly spec'd but my understanding is that sourceMappingURL and sourceRoot should be URIs or relative paths, not local absolute paths. In a browser, a path starting with / should be interpreted as relative to the webserver root.

In Node, Chrome Devtools handles this on Mac, but on Windows, it can't handle a sourceMappingUrl or sourceRoot as a windows-style absolute path. That is what convinces me that this is worth fixing on TS's end.

In vscode, I plan to try to support this scenario somehow, since it previously worked.