fix(json): Add newline at the end of json files (denoland/deno#6885)

fs/README.md

@@ -133,18 +133,24 @@ const foo = readJsonSync("./foo.json");
 
 Writes an object to a JSON file.
 
-**WriteJsonOptions**
+#### WriteJsonOptions
 
 - replacer : An array of strings and numbers that acts as a approved list for
   selecting the object properties that will be stringified.
 - space : Adds indentation, white space, and line break characters to the
   return-value JSON text to make it easier to read.
 
+You can also specify options from `Deno.WriteFileOptions` to configure how the
+file is written.
+
 ```ts
 import { writeJson, writeJsonSync } from "https://deno.land/std/fs/mod.ts";
 
 writeJson("./target.dat", { foo: "bar" }, { spaces: 2 }); // returns a promise
 writeJsonSync("./target.dat", { foo: "bar" }, { replacer: ["foo"] }); // void
+
+// appends to the file instead of rewriting
+writeJsonSync("./target.dat", { foo: "bar" }, { append: true });
 ```
 
 ### walk

fs/write_json.ts

@@ -2,9 +2,28 @@
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 type Replacer = (key: string, value: any) => any;
 
-export interface WriteJsonOptions {
+export interface WriteJsonOptions extends Deno.WriteFileOptions {
-  spaces?: number | string;
   replacer?: Array<number | string> | Replacer;
+  spaces?: number | string;
+}
+
+function serialize(
+  filePath: string,
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  object: any,
+  options: WriteJsonOptions,
+): string {
+  try {
+    const jsonString = JSON.stringify(
+      object,
+      options.replacer as string[],
+      options.spaces,
+    );
+    return `${jsonString}\n`;
+  } catch (err) {
+    err.message = `${filePath}: ${err.message}`;
+    throw err;
+  }
 }
 
 /* Writes an object to a JSON file. */
@@ -14,20 +33,12 @@ export async function writeJson(
   object: any,
   options: WriteJsonOptions = {},
 ): Promise<void> {
-  let contentRaw = "";
+  const jsonString = serialize(filePath, object, options);
-
+  await Deno.writeTextFile(filePath, jsonString, {
-  try {
+    append: options.append,
-    contentRaw = JSON.stringify(
+    create: options.create,
-      object,
+    mode: options.mode,
-      options.replacer as string[],
+  });
-      options.spaces,
-    );
-  } catch (err) {
-    err.message = `${filePath}: ${err.message}`;
-    throw err;
-  }
-
-  await Deno.writeFile(filePath, new TextEncoder().encode(contentRaw));
 }
 
 /* Writes an object to a JSON file. */
@@ -37,18 +48,10 @@ export function writeJsonSync(
   object: any,
   options: WriteJsonOptions = {},
 ): void {
-  let contentRaw = "";
+  const jsonString = serialize(filePath, object, options);
-
+  Deno.writeTextFileSync(filePath, jsonString, {
-  try {
+    append: options.append,
-    contentRaw = JSON.stringify(
+    create: options.create,
-      object,
+    mode: options.mode,
-      options.replacer as string[],
+  });
-      options.spaces,
-    );
-  } catch (err) {
-    err.message = `${filePath}: ${err.message}`;
-    throw err;
-  }
-
-  Deno.writeFileSync(filePath, new TextEncoder().encode(contentRaw));
 }

fs/write_json_test.ts

@@ -25,7 +25,7 @@ Deno.test("writeJsonIfNotExists", async function (): Promise<void> {
 
   await Deno.remove(notExistsJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}\n`);
 });
 
 Deno.test("writeJsonIfExists", async function (): Promise<void> {
@@ -46,7 +46,7 @@ Deno.test("writeJsonIfExists", async function (): Promise<void> {
 
   await Deno.remove(existsJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}\n`);
 });
 
 Deno.test("writeJsonIfExistsAnInvalidJson", async function (): Promise<void> {
@@ -71,7 +71,7 @@ Deno.test("writeJsonIfExistsAnInvalidJson", async function (): Promise<void> {
 
   await Deno.remove(existsInvalidJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}\n`);
 });
 
 Deno.test("writeJsonWithSpaces", async function (): Promise<void> {
@@ -93,7 +93,7 @@ Deno.test("writeJsonWithSpaces", async function (): Promise<void> {
 
   await Deno.remove(existsJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{\n  "a": "1"\n}`);
+  assertEquals(new TextDecoder().decode(content), `{\n  "a": "1"\n}\n`);
 });
 
 Deno.test("writeJsonWithReplacer", async function (): Promise<void> {
@@ -121,7 +121,7 @@ Deno.test("writeJsonWithReplacer", async function (): Promise<void> {
 
   await Deno.remove(existsJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}\n`);
 });
 
 Deno.test("writeJsonSyncIfNotExists", function (): void {
@@ -140,7 +140,7 @@ Deno.test("writeJsonSyncIfNotExists", function (): void {
 
   Deno.removeSync(notExistsJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}\n`);
 });
 
 Deno.test("writeJsonSyncIfExists", function (): void {
@@ -161,7 +161,7 @@ Deno.test("writeJsonSyncIfExists", function (): void {
 
   Deno.removeSync(existsJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}\n`);
 });
 
 Deno.test("writeJsonSyncIfExistsAnInvalidJson", function (): void {
@@ -186,10 +186,10 @@ Deno.test("writeJsonSyncIfExistsAnInvalidJson", function (): void {
 
   Deno.removeSync(existsInvalidJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}\n`);
 });
 
-Deno.test("writeJsonWithSpaces", function (): void {
+Deno.test("writeJsonSyncWithSpaces", function (): void {
   const existsJsonFile = path.join(testdataDir, "file_write_spaces_sync.json");
 
   const invalidJsonContent = new TextEncoder().encode();
@@ -208,10 +208,10 @@ Deno.test("writeJsonWithSpaces", function (): void {
 
   Deno.removeSync(existsJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{\n  "a": "1"\n}`);
+  assertEquals(new TextDecoder().decode(content), `{\n  "a": "1"\n}\n`);
 });
 
-Deno.test("writeJsonWithReplacer", function (): void {
+Deno.test("writeJsonSyncWithReplacer", function (): void {
   const existsJsonFile = path.join(
     testdataDir,
     "file_write_replacer_sync.json",
@@ -239,5 +239,5 @@ Deno.test("writeJsonWithReplacer", function (): void {
 
   Deno.removeSync(existsJsonFile);
 
-  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}\n`);
 });