lib/cmd.js
function idToPath(id, config) {
    var alias = config.alias || {};
    return alias.hasOwnProperty(id) ?
        path.resolve(alias[id]) :
        path.resolve(config.base, id) + '.js';
}
function idToPath(id, config) {
    var alias = config.alias || {};
    return alias.hasOwnProperty(id) ?
        path.resolve(alias[id]) :
        path.resolve(config.base, id) + '.js';
}
function idToPath ( id , config ) { var alias = config . alias || { } ; return alias . hasOwnProperty ( id ) ? path . resolve ( alias [ id ] ) : path . resolve ( config . base , id ) + '.js' ; }
Convert toplevel module id to filepath
@private
Convert toplevel module id to filepath