index.js

'use strict';

const Parser = require('@typescript-eslint/typescript-estree');
const Walker = require('node-source-walk');
const types = require('ast-module-types');

/**
 * Extracts the dependencies of the supplied TypeScript module
 *
 * @param  {String|Object} src - File's content or AST
 * @return {String[]}
 */
module.exports = function(src, options = {}) {

  const walkerOptions = Object.assign({}, options, {parser: Parser});

  // Determine whether to skip "type-only" imports
  // https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-9.html#import-types
  // https://www.typescriptlang.org/v2/docs/handbook/release-notes/typescript-3-8.html#type-only-imports-and-export
  const skipTypeImports = Boolean(options.skipTypeImports);
  // Remove skipTypeImports option, as this option may not be recognized by the walker/parser
  delete walkerOptions.skipTypeImports;

  const mixedImports = Boolean(options.mixedImports);
  delete walkerOptions.mixedImports;

  const walker = new Walker(walkerOptions);

  const dependencies = [];

  if (typeof src === 'undefined') {
    throw new Error('src not given');
  }

  if (src === '') {
    return dependencies;
  }

  walker.walk(src, function(node) {
    switch (node.type) {
      case 'ImportExpression':
        if (!options.skipAsyncImports && node.source && node.source.value) {
          dependencies.push({ value: node.source.value });
        }
        break;
      case 'ImportDeclaration':
        if (skipTypeImports && node.importKind == 'type') {
          break;
        }
        if (node.source && node.source.value) {
          dependencies.push({ value: node.source.value, specifiers: node.specifiers?.map(s => s.imported?.name) });
        }
        break;
      case 'ExportNamedDeclaration':
      case 'ExportAllDeclaration':
        if (node.source && node.source.value) {
          dependencies.push({ value: node.source.value });
        }
        break;
      case 'TSExternalModuleReference':
        if (node.expression && node.expression.value) {
          dependencies.push({ value: node.expression.value });
        }
        break;
      case 'TSImportType':
        if (!skipTypeImports && node.parameter.type === 'TSLiteralType') {
          dependencies.push({ value: node.parameter.literal.value });
        }
        break;
      case 'CallExpression':
        if (!mixedImports || !types.isRequire(node) ||
            !node.arguments ||
            !node.arguments.length) {
          break;
        }

        if (types.isPlainRequire(node)) {
          const result = extractDependencyFromRequire(node);
          if (result) {
            dependencies.push({ value: result });
          }
        } else if (types.isMainScopedRequire(node)) {
          dependencies.push({ value: extractDependencyFromMainRequire(node) });
        }

        break;
      default:
        return;
    }
  });

  return dependencies;
};

module.exports.tsx = function(src, options) {
  return module.exports(src, Object.assign({}, options, { jsx: true }));
};

function extractDependencyFromRequire(node) {
  if (node.arguments[0].type === 'Literal' || node.arguments[0].type === 'StringLiteral') {
    return node.arguments[0].value;
  } else if (node.arguments[0].type === 'TemplateLiteral') {
    return node.arguments[0].quasis[0].value.raw;
  }
}

function extractDependencyFromMainRequire(node) {
  return node.arguments[0].value;
}