Option to resolve absolute path relative to options.rootDir

[buckle2000]

🙋 feature request

Add an option to set "relative" absolute path.

🤔 Expected Behavior

If option --root-dir is given to parcel, absolute path should resolve relative to that path.

Example: parcel src/index.html --root-dir src

😯 Current Behavior

Any absolute path in assets is resolved to filesystem root /.

💁 Possible Solution

When resolving dependencies, change all path.resolve to the following function:

const rootDir = '/home/user/some/path'

function resolvePath(...paths) {
    const rawPath = path.resolve(...paths)
    if (rootDir !== undefined) {
        if (path.isAbsolute(rawPath)) {
            return path.join(rootDir, rawPath)
        } else {
            return rawPath
        }
    } else {
        return rawPath
    }
}

For example, change
const absPath = Path.resolve(Path.dirname(asset.name), dep.name);
to
const absPath = resolvePath(Path.dirname(asset.name), dep.name);

🔦 Context

Closes #1352

💻 Examples