Add function to flatten single file (#527)

* Add function to flatten single file

* Add changeset

.changeset/tough-crabs-drive.md

@@ -0,0 +1,14 @@
+---
+"@ethereum-waffle/compiler": minor
+"@ethereum-waffle/chai": minor
+"ethereum-waffle": minor
+"@ethereum-waffle/e2e": minor
+"@ethereum-waffle/ens": minor
+"@ethereum-waffle/jest": minor
+"@ethereum-waffle/mock-contract": minor
+"@ethereum-waffle/provider": minor
+---
+
+- Fix vulnerabilities shown by `yarn audit`
+- Fix typings in `closeTo` matcher
+- Add `flattenSingleFile` function to compiler

waffle-compiler/src/flattener.ts

@@ -23,6 +23,20 @@ export async function flattenAndSave(input: InputConfig) {
   await saveToFile(output, config);
 }
 
+const getFileName = (rootContract: GatheredContractInterface) => path.parse(rootContract.url).base;
+
+const getFilePath = (fileName: string, outputDirectory: string) => path.join(outputDirectory, fileName);
+
+export async function flattenSingleFile(input: InputConfig, name: string) {
+  const config = inputToConfig(input);
+  const output = await getContractDependency(config);
+  const contract = output.find((contracts) => getFileName(contracts[contracts.length - 1]) === name);
+  if (!contract) {
+    return null;
+  }
+  return getFlattenedSource(contract, '').sourceWithNormalizedLicences;
+}
+
 async function getContractDependency(config: Config): Promise<GatheredContractInterface[][]> {
   const resolver = ImportsFsEngine().addResolver(
     resolvers.BacktrackFsResolver(config.nodeModulesDirectory)
@@ -44,6 +58,17 @@ const fsOps = {
 
 const unique = <T>(arr: T[]) => [...new Set(arr)];
 
+function getFlattenedSource(contract: Array<GatheredContractInterface>, outputDirectory: string) {
+  const rootContract = contract[contract.length - 1];
+  const fileName = getFileName(rootContract);
+  const filePath = getFilePath(fileName, outputDirectory);
+
+  const contractsWithCommentedDirectives = contract.map(replaceDirectivesWithComments(rootContract));
+  const source = ''.concat(...unique(contractsWithCommentedDirectives));
+  const sourceWithNormalizedLicences = normalizeSpdxLicenceIdentifiers(source, fileName);
+  return {filePath, sourceWithNormalizedLicences};
+}
+
 function saveToFile(
   output: GatheredContractInterface[][],
   config: Config,
@@ -54,13 +79,7 @@ function saveToFile(
   fileSystem.createDirectory(outputDirectory);
 
   output.map((contract: Array<GatheredContractInterface>) => {
-    const rootContract = contract[contract.length - 1];
-    const fileName = path.parse(rootContract.url).base;
-    const filePath = path.join(outputDirectory, fileName);
-
-    const contractsWithCommentedDirectives = contract.map(replaceDirectivesWithComments(rootContract));
-    const source = ''.concat(...unique(contractsWithCommentedDirectives));
-    const sourceWithNormalizedLicences = normalizeSpdxLicenceIdentifiers(source, fileName);
+    const {filePath, sourceWithNormalizedLicences} = getFlattenedSource(contract, outputDirectory);
 
     fileSystem.writeFile(filePath, sourceWithNormalizedLicences);
   });

waffle-compiler/test/flattener/flattener.ts

@@ -1,7 +1,6 @@
 import {expect} from 'chai';
 import fs from 'fs-extra';
-import {inputToConfig} from '../../src/config';
-import {flattenAndSave, normalizeSpdxLicenceIdentifiers} from '../../src';
+import {inputToConfig, flattenAndSave, flattenSingleFile, normalizeSpdxLicenceIdentifiers} from '../../src';
 
 const sourceDirectory = './test/flattener/testSource';
 const flattenOutputDirectory = './test/flattener/flattenFiles';
@@ -60,4 +59,9 @@ describe('flattening', () => {
                   test3
             `);
   });
+
+  it('single file flattening', async () => {
+    const expectedFile = fs.readFileSync('./test/flattener/expectedFlattenChild.sol', 'utf8');
+    expect(await flattenSingleFile(config, 'child.sol')).to.equal(expectedFile);
+  });
 });