Git based diff utility for NodeJS

diff.ts

import {join} from 'path';
import fs from "fs";
import os from "os";
import {spawnSync} from "child_process";

/**
 * Use the local `git` executable to render a diff between two strings.
 * This is intended for test/development environments. Consider using
 * `jsdiff` if you need to compare potentially malicious strings. 
 */
function gitDiffStrings(actual: string, expected: string) {
  const basePath = path.join(os.tmpdir(), 'node_git_diff_render');
  const tmpDir = fs.mkdtempSync(basePath);
  const actualPath = path.join(tmpDir, 'actual');
  const expectedPath = path.join(tmpDir, 'expected');

  fs.writeFileSync(actualPath, `${actual}\n`, {mode: 0o600})
  fs.writeFileSync(expectedPath, `${expected}\n`, {mode: 0o600})
  const res = spawnSync('git', [
    'diff',
    '--no-index',
    '--color=always',
    'expected',
    'actual',
  ], {cwd: tmpDir});
  fs.rmdirSync(tmpDir, {recursive: true});
  return res.stdout.toString();
}