TypeScript compiler API get value / type of import

Consider the following code:

// file1
export const VIEWPORT_HEIGHT = 1080;

// file2
import { VIEWPORT_HEIGHT } from '../../constants/app';

While processing file2, how can I get the value / type of VIEWPORT_HEIGHT? Given that it's a constant, its type will be 1080, not number. I'm trying to accomplish the same as VSCode which shows the constant value when you hover over the import:

While processing the import, I can analyse the following AST:

ImportDeclaration > ImportClause > NamedImports > ImportSpecifier > Identifier

I have access to the program that webpack's ts-loader passes to getCustomTransformers and thus I have access to the type checker by doing:

let checker = program.getTypeChecker();

But I'm unable to reach the value / type. What am I missing?

I've figured this out.

I can pass any declaration to the type checker to obtain its value. Here's an example:

const ts = require('typescript');

function createConstInlinerTransformer(program) {
  const factory = ts.factory;
  const checker = program.getTypeChecker();

  function transformerFactory(context) {
    return {
      transformSourceFile(sourceFile) {
        const visitor = function (node) {
          // The sourceFile node contains the following:
          // sourceFile.symbol.exports
          // sourceFile.locals
          // We can use these to obtain the values of variables and imports.

          // import
          const firstImportClause = sourceFile.statements[0].importClause;
          checker.getTypeAtLocation(firstImportClause.namedBindings.elements[0].symbol.declarations[0])

          // local const
          const localVar = sourceFile.locals.get('someVar');
          checker.getTypeAtLocation(localVar.valueDeclaration);

          // exported const
          const exportedVar = sourceFile.symbol.exports.get('someExportedVar');
          checker.getTypeAtLocation(exportedVar.valueDeclaration)

          return ts.visitEachChild(node, visitor, context);
        };

        return ts.visitNode(sourceFile, visitor);
      },
    };
  }
  return transformerFactory;
}

module.exports = { createConstInlinerTransformer };