fix(repo): fix flaky cross-os new line check (#5938)

e2e/cli/src/cli.test.ts

@@ -270,6 +270,9 @@ describe('migrate', () => {
     // updates package.json
     const packageJson = readJson(`package.json`);
     expect(packageJson.dependencies['migrate-child-package']).toEqual('9.0.0');
+    // should keep new line on package
+    const packageContent = readFile('package.json');
+    expect(packageContent.charCodeAt(packageContent.length - 1)).toEqual(10);
 
     // creates migrations.json
     const migrationsJson = readJson(`migrations.json`);

e2e/utils/index.ts

@@ -472,7 +472,7 @@ export function readJson(f: string): any {
 
 export function readFile(f: string) {
   const ff = f.startsWith('/') ? f : tmpProjPath(f);
-  return readFileSync(ff).toString();
+  return readFileSync(ff, 'utf-8');
 }
 
 export function rmDist() {

packages/tao/src/commands/migrate.ts

@@ -13,7 +13,11 @@ import {
 } from '../shared/package-manager';
 import { FsTree } from '../shared/tree';
 import { flushChanges } from './generate';
-import { readJsonFile, writeJsonFile } from '../utils/fileutils';
+import {
+  JsonReadOptions,
+  readJsonFile,
+  writeJsonFile,
+} from '../utils/fileutils';
 
 export type MigrationsJson = {
   version: string;
@@ -503,7 +507,8 @@ function updatePackageJson(
   }
 ) {
   const packageJsonPath = join(root, 'package.json');
-  const json = readJsonFile(packageJsonPath);
+  const parseOptions: JsonReadOptions = {};
+  const json = readJsonFile(packageJsonPath, parseOptions);
   Object.keys(updatedPackages).forEach((p) => {
     if (json.devDependencies && json.devDependencies[p]) {
       json.devDependencies[p] = updatedPackages[p].version;
@@ -514,7 +519,9 @@ function updatePackageJson(
       json.dependencies[p] = updatedPackages[p].version;
     }
   });
-  writeJsonFile(packageJsonPath, json);
+  writeJsonFile(packageJsonPath, json, {
+    appendNewLine: parseOptions.endsWithNewline,
+  });
 }
 
 async function generateMigrationsJsonAndUpdatePackageJson(

packages/tao/src/utils/fileutils.ts

@@ -4,6 +4,22 @@ import { readFileSync, writeFileSync } from 'fs';
 import { dirname } from 'path';
 import { ensureDirSync } from 'fs-extra';
 
+export interface JsonReadOptions extends JsonParseOptions {
+  /**
+   * mutable field recording whether JSON ends with new line
+   * @default false
+   */
+  endsWithNewline?: boolean;
+}
+
+export interface JsonWriteOptions extends JsonSerializeOptions {
+  /**
+   * whether to append new line at the end of JSON file
+   * @default false
+   */
+  appendNewLine?: boolean;
+}
+
 /**
  * Reads a JSON file and returns the object the JSON content represents.
  *
@@ -13,9 +29,13 @@ import { ensureDirSync } from 'fs-extra';
  */
 export function readJsonFile<T extends object = any>(
   path: string,
-  options?: JsonParseOptions
+  options?: JsonReadOptions
 ): T {
-  return parseJson<T>(readFileSync(path, 'utf-8'), options);
+  const content = readFileSync(path, 'utf-8');
+  if (options) {
+    options.endsWithNewline = content.charCodeAt(content.length - 1) === 10;
+  }
+  return parseJson<T>(content, options);
 }
 
 /**
@@ -28,8 +48,12 @@ export function readJsonFile<T extends object = any>(
 export function writeJsonFile<T extends object = object>(
   path: string,
   data: T,
-  options?: JsonSerializeOptions
+  options?: JsonWriteOptions
 ): void {
   ensureDirSync(dirname(path));
-  writeFileSync(path, serializeJson(data, options), { encoding: 'utf-8' });
+  const serializedJson = serializeJson(data, options);
+  const content = options?.appendNewLine
+    ? `${serializedJson}\n`
+    : serializedJson;
+  writeFileSync(path, content, { encoding: 'utf-8' });
 }