demo/typescript.js
function getScopeNode(initialToken, position, sourceFile) {
                var scope = initialToken;
                while (scope && !ts.positionBelongsToNode(scope, position, sourceFile)) {
                    scope = scope.parent;
                }
                return scope;
            }
function getScopeNode(initialToken, position, sourceFile) {
                var scope = initialToken;
                while (scope && !ts.positionBelongsToNode(scope, position, sourceFile)) {
                    scope = scope.parent;
                }
                return scope;
            }
Finds the first node that "embraces" the position, so that one may
accurately aggregate locals from the closest containing scope.