tslint-folders/src/tsfFoldersImportsBetweenPackagesRule.ts

import * as Lint from "tslint";
import * as ts from "typescript";

import { ConfigFactory } from "./config/ConfigFactory";
import { GeneralRuleUtils } from "./utils/GeneralRuleUtils";
import { ImportRuleUtils, PathSource } from "./utils/ImportRuleUtils";

export const IMPORTS_BETWEEN_PACKAGES_RULE_ID =
  "tsf-folders-imports-between-packages";

const DISALLOW_IMPORT_FROM_SELF_MESSAGE =
  "do not import a package from itself - use a relative path";

export class Rule extends Lint.Rules.AbstractRule {
  apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
    const walker = new ImportsWalker(sourceFile, this.getOptions());
    this.applyWithWalker(walker);

    return walker.getFailures();
  }
}

class ImportsWalker extends Lint.RuleWalker {
  visitImportDeclaration(node: ts.ImportDeclaration) {
    this.validate(node, node.moduleSpecifier.getText());
  }

  visitImportEqualsDeclaration(node: ts.ImportEqualsDeclaration) {
    this.validate(node, node.moduleReference.getText());

    super.visitImportEqualsDeclaration(node);
  }

  private validate(node: ts.Node, text: string) {
    // algorithm:
    /*
        - determine this files PackageFolder, PackageSubFolder
        - if ThirdParty then skip
        - determine the PackageFolder, PackageSubFolder of the import
        - if ThirdParty then skip
        - disallowImportFromSelf -> disallow if same
        - check if the import is allowed
        */

    const config = ConfigFactory.createForBetweenPackages(this.getOptions());

    const thisPackageLocation = ImportRuleUtils.determinePackageLocationFromPath(
      node.getSourceFile().fileName,
      IMPORTS_BETWEEN_PACKAGES_RULE_ID,
      config,
      PathSource.SourceFilePath
    );

    if (ImportRuleUtils.isThisPackageThirdParty(thisPackageLocation, node)) {
      return;
    }

    if (!thisPackageLocation.packageFolder) {
      throw new Error(
        "unexpected: this package is not ThirdParty, but has no packageFolder in its location"
      );
    }

    const importPackageLocation = ImportRuleUtils.determinePackageLocationFromPath(
      text,
      IMPORTS_BETWEEN_PACKAGES_RULE_ID,
      config,
      PathSource.ImportText,
      thisPackageLocation
    );

    ImportRuleUtils.logPackageAndImport(
      node,
      thisPackageLocation,
      importPackageLocation
    );

    const isImportRecognised = !ImportRuleUtils.isPackageThirdParty(
      importPackageLocation
    );

    if (
      isImportRecognised &&
      importPackageLocation.packageName === thisPackageLocation.packageName &&
      config.disallowImportFromSelf.enabled &&
      !ImportRuleUtils.shouldIgnoreFile(
        node,
        config.disallowImportFromSelf.ignorePaths
      )
    ) {
      this.addFailureAtNode(
        node,
        GeneralRuleUtils.buildFailureString(
          DISALLOW_IMPORT_FROM_SELF_MESSAGE,
          IMPORTS_BETWEEN_PACKAGES_RULE_ID
        )
      );
      return;
    }

    if (
      isImportRecognised &&
      config.checkImportsBetweenPackages.enabled &&
      !ImportRuleUtils.shouldIgnoreFile(
        node,
        config.checkImportsBetweenPackages.ignorePaths
      )
    ) {
      if (
        !thisPackageLocation.packageFolder ||
        !importPackageLocation.packageFolder
      ) {
        return;
      }

      if (
        importPackageLocation.packageFolder ===
        thisPackageLocation.packageFolder
      ) {
        if (!config.checkImportsBetweenPackages.checkSubFoldersEnabled) {
          return;
        }

        // TODO xxx extract fun?
        // check sub-folders

        if (
          thisPackageLocation.packageSubFolder &&
          importPackageLocation.packageSubFolder &&
          thisPackageLocation.packageSubFolder.importPath !==
            importPackageLocation.packageSubFolder.importPath
        ) {
          if (
            thisPackageLocation.packageSubFolder.allowedToImport.some(
              allowed => allowed === "*"
            )
          ) {
            return;
          }

          if (
            !thisPackageLocation.packageSubFolder.allowedToImport.some(
              allowed => {
                return (
                  importPackageLocation.packageSubFolder!.importPath === allowed
                );
              }
            )
          ) {
            const failureMessage = `'${
              thisPackageLocation.packageName
            }' sub folder '${
              thisPackageLocation.packageSubFolder.importPath
            }' is not allowed to import from '${
              importPackageLocation.packageSubFolder.importPath
            }'`;

            this.addFailureAtNodeWithMessage(node, failureMessage);
          }
        }
      } else {
        const thisPackageFolder = thisPackageLocation.packageFolder;
        if (
          thisPackageFolder.allowedToImport.find(allowed => allowed === "*")
        ) {
          return;
        }

        if (
          !thisPackageFolder.allowedToImport.find(
            allowed => allowed === importPackageLocation.packageName
          )
        ) {
          const failureMessage = `'${
            thisPackageLocation.packageName
          }' is not allowed to import from '${
            importPackageLocation.packageName
          }'`;

          this.addFailureAtNodeWithMessage(node, failureMessage);
        }
      }
    }
  }

  private addFailureAtNodeWithMessage(node: ts.Node, failureMessage: string) {
    this.addFailureAtNode(
      node,
      GeneralRuleUtils.buildFailureString(
        failureMessage,
        IMPORTS_BETWEEN_PACKAGES_RULE_ID
      )
    );
  }
}