Atomic write

package-lock.json

@@ -1238,6 +1238,15 @@
       "integrity": "sha512-l42BggppR6zLmpfU6fq9HEa2oGPEI8yrSPL3GITjfRInppYFahObbIQOQK3UGxEnyQpltZLaPe75046NOZQikw==",
       "dev": true
     },
+    "@types/write-file-atomic": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/@types/write-file-atomic/-/write-file-atomic-3.0.0.tgz",
+      "integrity": "sha512-XrvNv7CBEveBoWkGU4ZxuyeL7iaYVr609VjlNAe+VaS8N9stTvGwp5IZgFP+QDbiRQV/R7MmipPsgAhlf5LZzQ==",
+      "dev": true,
+      "requires": {
+        "@types/node": "*"
+      }
+    },
     "@types/yargs": {
       "version": "15.0.4",
       "resolved": "https://registry.npmjs.org/@types/yargs/-/yargs-15.0.4.tgz",
@@ -3530,8 +3539,7 @@
     "imurmurhash": {
       "version": "0.1.4",
       "resolved": "https://registry.npmjs.org/imurmurhash/-/imurmurhash-0.1.4.tgz",
-      "integrity": "sha1-khi5srkoojixPcT7a21XbyMUU+o=",
-      "dev": true
+      "integrity": "sha1-khi5srkoojixPcT7a21XbyMUU+o="
     },
     "inflight": {
       "version": "1.0.6",
@@ -7761,7 +7769,6 @@
       "version": "3.1.5",
       "resolved": "https://registry.npmjs.org/typedarray-to-buffer/-/typedarray-to-buffer-3.1.5.tgz",
       "integrity": "sha512-zdu8XMNEDepKKR+XYOXAVPtWui0ly0NtohUscw+UmaHiAWT8hrV1rr//H6V+0DvJ3OQ19S979M0laLfX8rm82Q==",
-      "dev": true,
       "requires": {
         "is-typedarray": "^1.0.0"
       }
@@ -8232,7 +8239,6 @@
       "version": "3.0.3",
       "resolved": "https://registry.npmjs.org/write-file-atomic/-/write-file-atomic-3.0.3.tgz",
       "integrity": "sha512-AvHcyZ5JnSfq3ioSyjrBkH9yW4m7Ayk8/9My/DD9onKeu/94fwrMocemO2QAJFAlnnDN+ZDS+ZjAR5ua1/PV/Q==",
-      "dev": true,
       "requires": {
         "imurmurhash": "^0.1.4",
         "is-typedarray": "^1.0.0",

package.json

@@ -12,6 +12,7 @@
     "react": "^16.13.0",
     "react-dom": "^16.13.0",
     "smtp-server": "^3.6.0",
+    "write-file-atomic": "^3.0.3",
     "xmlbuilder2": "^2.1.0"
   },
   "devDependencies": {
@@ -24,6 +25,7 @@
     "@types/react": "^16.9.29",
     "@types/react-dom": "^16.9.5",
     "@types/smtp-server": "^3.5.4",
+    "@types/write-file-atomic": "^3.0.0",
     "axios": "^0.19.2",
     "concurrently": "^5.1.0",
     "jest": "^25.2.4",

src/index.tsx

@@ -5,6 +5,7 @@ import React from "react";
 import ReactDOMServer from "react-dom/server";
 import * as xmlbuilder2 from "xmlbuilder2";
 import { promises as fs } from "fs";
+import writeFileAtomic from "write-file-atomic";
 import cryptoRandomString from "crypto-random-string";
 
 export const webServer = express()
@@ -101,7 +102,7 @@ export const emailServer = new SMTPServer({
         xml.feed.entry.unshift(entry);
         while (xml.feed.entry.length > 0 && renderXML(xml).length > 500_000)
           xml.feed.entry.pop();
-        await fs.writeFile(path, renderXML(xml));
+        await writeFileAtomic(path, renderXML(xml));
       }
       callback();
     })().catch(error => {