Replaced some sync methods for their async version

src/createEslintConfig.ts

@@ -1,15 +1,16 @@
 import fs from 'fs';
 import path from 'path';
+import util from 'util';
 import { CLIEngine } from 'eslint';
 
 interface CreateEslintConfigArgs {
   rootDir: string;
   writeFile: boolean;
 }
-export function createEslintConfig({
+export async function createEslintConfig({
   rootDir,
   writeFile,
-}: CreateEslintConfigArgs): CLIEngine.Options['baseConfig'] {
+}: CreateEslintConfigArgs): Promise<CLIEngine.Options['baseConfig']> {
   const config = {
     extends: [
       'react-app',
@@ -18,24 +19,27 @@ export function createEslintConfig({
     ],
   };
 
-  if (writeFile) {
-    const file = path.join(rootDir, '.eslintrc.js');
-    if (fs.existsSync(file)) {
+  if (!writeFile) {
+    return config;
+  }
+
+  const file = path.join(rootDir, '.eslintrc.js');
+  try {
+    await util.promisify(fs.writeFile)(
+      file,
+      `module.exports = ${JSON.stringify(config, null, 2)}`,
+      { flag: 'wx' }
+    );
+  } catch (e) {
+    if (e.code === 'EEXIST') {
       console.error(
         'Error trying to save the Eslint configuration file:',
         `${file} already exists.`
       );
     } else {
-      try {
-        fs.writeFileSync(
-          file,
-          `module.exports = ${JSON.stringify(config, null, 2)}`
-        );
-      } catch (e) {
-        console.error(e);
-      }
+      console.error(e);
     }
-  }
 
-  return config;
+    return config;
+  }
 }

src/createRollupConfig.ts

@@ -20,8 +20,8 @@ const errorCodeOpts = {
 // shebang cache map thing because the transform only gets run once
 let shebang: any = {};
 
-export function createRollupConfig(opts: TsdxOptions) {
-  const findAndRecordErrorCodes = extractErrors({
+export async function createRollupConfig(opts: TsdxOptions) {
+  const findAndRecordErrorCodes = await extractErrors({
     ...errorCodeOpts,
     ...opts,
   });
@@ -88,8 +88,8 @@ export function createRollupConfig(opts: TsdxOptions) {
     },
     plugins: [
       !!opts.extractErrors && {
-        transform(source: any) {
-          findAndRecordErrorCodes(source);
+        async transform(source: any) {
+          await findAndRecordErrorCodes(source);
           return source;
         },
       },

src/errors/extractErrors.ts

@@ -28,7 +28,7 @@ const babylonOptions = {
   ],
 };
 
-export function extractErrors(opts: any) {
+export async function extractErrors(opts: any) {
   if (!opts || !('errorMapFilePath' in opts)) {
     throw new Error(
       'Missing options. Ensure you pass an object with `errorMapFilePath`.'
@@ -45,7 +45,7 @@ export function extractErrors(opts: any) {
     // Using `fs.readFileSync` instead of `require` here, because `require()`
     // calls are cached, and the cache map is not properly invalidated after
     // file changes.
-    existingErrorMap = JSON.parse(fs.readFileSync(errorMapFilePath, 'utf8'));
+    existingErrorMap = JSON.parse(await fs.readFile(errorMapFilePath, 'utf8'));
   } catch (e) {
     existingErrorMap = {};
   }
@@ -89,20 +89,20 @@ export function extractErrors(opts: any) {
     existingErrorMap[errorMsgLiteral] = '' + currentID++;
   }
 
-  function flush(cb?: any) {
+  async function flush() {
     const prettyName = pascalCase(safeVariableName(opts.name));
     // Ensure that the ./src/errors directory exists or create it
-    fs.ensureDirSync(paths.appErrors);
+    await fs.ensureDir(paths.appErrors);
 
     // Output messages to ./errors/codes.json
-    fs.writeFileSync(
+    await fs.writeFile(
       errorMapFilePath,
       JSON.stringify(invertObject(existingErrorMap), null, 2) + '\n',
       'utf-8'
     );
 
     // Write the error files, unless they already exist
-    fs.writeFileSync(
+    await fs.writeFile(
       paths.appErrors + '/ErrorDev.js',
       `
 function ErrorDev(message) {
@@ -116,7 +116,7 @@ export default ErrorDev;
       'utf-8'
     );
 
-    fs.writeFileSync(
+    await fs.writeFile(
       paths.appErrors + '/ErrorProd.js',
       `
 function ErrorProd(code) {
@@ -138,8 +138,8 @@ export default ErrorProd;
     );
   }
 
-  return function extractErrors(source: any) {
+  return async function extractErrors(source: any) {
     transform(source);
-    flush();
+    await flush();
   };
 }

src/getInstallCmd.ts

@@ -4,13 +4,13 @@ let cmd: InstallCommand;
 
 export type InstallCommand = 'yarn' | 'npm';
 
-export default function getInstallCmd(): InstallCommand {
+export default async function getInstallCmd(): Promise<InstallCommand> {
   if (cmd) {
     return cmd;
   }
 
   try {
-    execa.sync('yarnpkg', ['--version']);
+    await execa('yarnpkg', ['--version']);
     cmd = 'yarn';
   } catch (e) {
     cmd = 'npm';