refactor: use helpers to manage npm commands

This also speeds up tests and avoids us checking that npm did what it is supposed to do.

.changeset/pretty-flowers-bathe.md

@@ -0,0 +1,7 @@
+---
+"wrangler": patch
+---
+
+refactor: use helpers to manage npm commands
+
+This change speeds up tests and avoids us checking that npm did what it is supposed to do.

packages/wrangler/src/__tests__/index.test.ts

@@ -1,6 +1,8 @@
 import * as fs from "node:fs";
 import * as fsp from "node:fs/promises";
 import * as TOML from "@iarna/toml";
+import { version as wranglerVersion } from "../../package.json";
+import { npm } from "../npm-installer";
 import { mockConsoleMethods } from "./helpers/mock-console";
 import { mockConfirm } from "./helpers/mock-dialogs";
 import { runInTempDir } from "./helpers/run-in-tmp";
@@ -9,6 +11,11 @@ import { runWrangler } from "./helpers/run-wrangler";
 describe("wrangler", () => {
   runInTempDir();
 
+  beforeEach(() => {
+    jest.spyOn(npm, "addDevDep").mockResolvedValue();
+    jest.spyOn(npm, "install").mockResolvedValue();
+  });
+
   const std = mockConsoleMethods();
 
   describe("no command", () => {
@@ -153,6 +160,7 @@ describe("wrangler", () => {
         wrangler: expect.any(String),
       });
       expect(fs.existsSync("./tsconfig.json")).toBe(false);
+      expect(npm.install).toHaveBeenCalled();
     });
 
     it("should not touch an existing package.json in the same directory", async () => {
@@ -205,9 +213,7 @@ describe("wrangler", () => {
       );
       expect(packageJson.name).toEqual("test");
       expect(packageJson.version).toEqual("1.0.0");
-      expect(packageJson.devDependencies).toEqual({
-        wrangler: expect.any(String),
-      });
+      expect(npm.addDevDep).toHaveBeenCalledWith("wrangler", wranglerVersion);
     });
 
     it("should not touch an existing package.json in an ancestor directory", async () => {
@@ -265,13 +271,7 @@ describe("wrangler", () => {
       expect(tsconfigJson.compilerOptions.types).toEqual([
         "@cloudflare/workers-types",
       ]);
-      const packageJson = JSON.parse(
-        fs.readFileSync("./package.json", "utf-8")
-      );
-      expect(packageJson.devDependencies).toEqual({
-        "@cloudflare/workers-types": expect.any(String),
-        wrangler: expect.any(String),
-      });
+      expect(npm.addDevDep).toHaveBeenCalledWith("@cloudflare/workers-types");
     });
 
     it("should not touch an existing tsconfig.json in the same directory", async () => {
@@ -331,12 +331,7 @@ describe("wrangler", () => {
       );
       // unchanged tsconfig
       expect(tsconfigJson.compilerOptions).toEqual({});
-      const packageJson = JSON.parse(
-        fs.readFileSync("./package.json", "utf-8")
-      );
-      expect(packageJson.devDependencies).toEqual({
-        "@cloudflare/workers-types": expect.any(String),
-      });
+      expect(npm.addDevDep).toHaveBeenCalledWith("@cloudflare/workers-types");
     });
 
     it("should not touch an existing tsconfig.json in an ancestor directory", async () => {

packages/wrangler/src/index.tsx

@@ -3,7 +3,6 @@ import { readFile, writeFile } from "node:fs/promises";
 import path from "node:path/posix";
 import { setTimeout } from "node:timers/promises";
 import TOML from "@iarna/toml";
-import { execa } from "execa";
 import { findUp } from "find-up";
 import { render } from "ink";
 import React from "react";
@@ -25,6 +24,7 @@ import {
   createNamespace,
   isValidNamespaceBinding,
 } from "./kv";
+import { npm } from "./npm-installer";
 import { pages } from "./pages";
 import publish from "./publish";
 import { getAssetPaths } from "./sites";
@@ -38,8 +38,8 @@ import {
   getAccountId,
   validateScopeKeys,
 } from "./user";
-
 import { whoami } from "./whoami";
+
 import type { Config } from "./config";
 import type Yargs from "yargs";
 
@@ -234,9 +234,7 @@ export async function main(argv: string[]): Promise<void> {
               "  "
             ) + "\n"
           );
-          await execa("npm", ["install"], {
-            stdio: "inherit",
-          });
+          await npm.install();
           console.log(`✨ Created package.json`);
           pathToPackageJson = path.join(process.cwd(), "package.json");
         } else {
@@ -258,13 +256,7 @@ export async function main(argv: string[]): Promise<void> {
             "Would you like to install wrangler into your package.json?"
           );
           if (shouldInstall) {
-            await execa(
-              "npm",
-              ["install", `wrangler@${wranglerVersion}`, "--save-dev"],
-              {
-                stdio: "inherit",
-              }
-            );
+            await npm.addDevDep("wrangler", wranglerVersion);
             console.log(`✨ Installed wrangler`);
           }
         }
@@ -298,11 +290,7 @@ export async function main(argv: string[]): Promise<void> {
               "  "
             ) + "\n"
           );
-          await execa(
-            "npm",
-            ["install", "@cloudflare/workers-types", "--save-dev"],
-            { stdio: "inherit" }
-          );
+          await npm.addDevDep("@cloudflare/workers-types");
           console.log(
             `✨ Created tsconfig.json, installed @cloudflare/workers-types into devDependencies`
           );
@@ -324,13 +312,7 @@ export async function main(argv: string[]): Promise<void> {
             "Would you like to install the type definitions for Workers into your package.json?"
           );
           if (shouldInstall) {
-            await execa(
-              "npm",
-              ["install", "@cloudflare/workers-types", "--save-dev"],
-              {
-                stdio: "inherit",
-              }
-            );
+            await npm.addDevDep("@cloudflare/workers-types");
             // We don't update the tsconfig.json because
             // it could be complicated in existing projects
             // and we don't want to break them. Instead, we simply

packages/wrangler/src/npm-installer.ts

@@ -0,0 +1,24 @@
+import { execa } from "execa";
+
+/**
+ * Helpers for running npm commands
+ */
+export const npm = {
+  /** Add and install a new devDependency into the local package.json. */
+  async addDevDep(packageName: string, versionRange = "latest"): Promise<void> {
+    await execa(
+      "npm",
+      ["install", `${packageName}@${versionRange}`, "--save-dev"],
+      {
+        stdio: "inherit",
+      }
+    );
+  },
+
+  /** Install all the dependencies in the local package.json. */
+  async install(): Promise<void> {
+    await execa("npm", ["install"], {
+      stdio: "inherit",
+    });
+  },
+};