feat: throw unsupported OS error on a method call (#296)

src/get-default-printer/get-default-printer.spec.ts

@@ -2,6 +2,7 @@ import { mocked } from "ts-jest/utils";
 import getDefaultPrinter from "./get-default-printer";
 import execAsync from "../utils/exec-file-async";
 
+jest.mock("../utils/throw-if-unsupported-os");
 jest.mock("../utils/exec-file-async");
 const mockedExecAsync = mocked(execAsync);
 

src/get-default-printer/get-default-printer.ts

@@ -1,4 +1,5 @@
 import execFileAsync from "../utils/exec-file-async";
+import throwIfUnsupportedOperatingSystem from "../utils/throw-if-unsupported-os";
 import isValidPrinter from "../utils/windows-printer-valid";
 
 export interface Printer {
@@ -8,6 +9,8 @@ export interface Printer {
 
 async function getDefaultPrinter(): Promise<Printer | null> {
   try {
+    throwIfUnsupportedOperatingSystem();
+
     const { stdout } = await execFileAsync("Powershell.exe", [
       "-Command",
       "Get-CimInstance Win32_Printer -Property DeviceID,Name -Filter Default=true",

src/get-printers/get-printers.spec.ts

@@ -2,6 +2,7 @@ import { mocked } from "ts-jest/utils";
 import execAsync from "../utils/exec-file-async";
 import getPrinters from "./get-printers";
 
+jest.mock("../utils/throw-if-unsupported-os");
 jest.mock("../utils/exec-file-async");
 const mockedExecAsync = mocked(execAsync);
 

src/get-printers/get-printers.ts

@@ -1,5 +1,6 @@
 import execFileAsync from "../utils/exec-file-async";
 import isValidPrinter from "../utils/windows-printer-valid";
+import throwIfUnsupportedOperatingSystem from "../utils/throw-if-unsupported-os";
 import { Printer } from "../get-default-printer/get-default-printer";
 
 async function getPrinters(): Promise<Printer[]> {
@@ -22,6 +23,7 @@ async function getPrinters(): Promise<Printer[]> {
   }
 
   try {
+    throwIfUnsupportedOperatingSystem();
     const { stdout } = await execFileAsync("Powershell.exe", [
       "-Command",
       "Get-CimInstance Win32_Printer -Property DeviceID,Name",

src/index.spec.ts

@@ -12,17 +12,3 @@ test("has `print`, `getDefaultPrinter` and `getPrinters` methods", () => {
   expect(printer.getDefaultPrinter).toBeDefined();
   expect(printer.getPrinters).toBeDefined();
 });
-
-test.each(["linux", "darwin", "test"])(
-  "throws on unsupported platform %i",
-  (platform) => {
-    jest.resetModules();
-
-    const os = require("os");
-    os.platform.mockImplementation(() => platform);
-
-    expect(() => require("./index")).toThrowError(
-      new Error("Platform not supported")
-    );
-  }
-);

src/index.ts

@@ -1,8 +1,3 @@
 export { default as print } from "./print/print";
 export { default as getPrinters } from "./get-printers/get-printers";
 export { default as getDefaultPrinter } from "./get-default-printer/get-default-printer";
-import os from "os";
-
-if (os.platform() !== "win32") {
-  throw new Error("Platform not supported");
-}

src/print/print.spec.ts

@@ -9,7 +9,7 @@ jest.mock("fs");
 jest.mock("path");
 jest.mock("../utils/exec-file-async");
 jest.mock("../utils/electron-util");
-
+jest.mock("../utils/throw-if-unsupported-os");
 const mockedFixPathForAsarUnpack = mocked(fixPathForAsarUnpack);
 const mockedExistsSync = mocked(existsSync);
 const mockedExecAsync = mocked(execAsync);

src/print/print.ts

@@ -2,6 +2,7 @@ import path from "path";
 import fs from "fs";
 import execAsync from "../utils/exec-file-async";
 import fixPathForAsarUnpack from "../utils/electron-util";
+import throwIfUnsupportedOperatingSystem from "../utils/throw-if-unsupported-os";
 
 export interface PrintOptions {
   printer?: string;
@@ -38,6 +39,7 @@ export default async function print(
   pdf: string,
   options: PrintOptions = {}
 ): Promise<void> {
+  throwIfUnsupportedOperatingSystem();
   if (!pdf) throw "No PDF specified";
   if (!fs.existsSync(pdf)) throw "No such file";
 

src/utils/throw-if-unsupported-os.spec.ts

@@ -0,0 +1,24 @@
+jest.mock("os");
+
+let os;
+let throwIfUnsupportedOs;
+
+beforeEach(() => {
+  jest.resetModules();
+  os = require("os");
+  throwIfUnsupportedOs = require("./throw-if-unsupported-os").default;
+});
+
+it("does not throw on Windows", () => {
+  os.platform.mockImplementation(() => "win32");
+  expect(() => throwIfUnsupportedOs()).not.toThrowError();
+});
+
+["linux", "darwin", "test"].forEach((platform) => {
+  it(`throws on unsupported platform ${platform}`, () => {
+    os.platform.mockImplementation(() => platform);
+    expect(() => throwIfUnsupportedOs()).toThrowError(
+      "Operating System not supported"
+    );
+  });
+});

src/utils/throw-if-unsupported-os.ts

@@ -0,0 +1,7 @@
+import os from "os";
+
+export default function throwIfUnsupportedOs() {
+  if (os.platform() !== "win32") {
+    throw "Operating System not supported";
+  }
+}