decorate-angular-cli.js

/**
 * This file decorates the Angular CLI with the Nx CLI to enable features such as computation caching
 * and faster execution of tasks.
 *
 * It does this by:
 *
 * - Patching the Angular CLI to warn you in case you accidentally use the undecorated ng command.
 * - Symlinking the ng to nx command, so all commands run through the Nx CLI
 * - Updating the package.json postinstall script to give you control over this script
 *
 * The Nx CLI decorates the Angular CLI, so the Nx CLI is fully compatible with it.
 * Every command you run should work the same when using the Nx CLI, except faster.
 *
 * Because of symlinking you can still type `ng build/test/lint` in the terminal. The ng command, in this case,
 * will point to nx, which will perform optimizations before invoking ng. So the Angular CLI is always invoked.
 * The Nx CLI simply does some optimizations before invoking the Angular CLI.
 *
 * To opt out of this patch:
 * - Replace occurrences of nx with ng in your package.json
 * - Remove the script from your postinstall script in your package.json
 * - Delete and reinstall your node_modules
 */

 const fs = require("fs");
 const os = require("os");
 const cp = require("child_process");
 const isWindows = os.platform() === "win32";
 let output;
 try {
   output = require("@nrwl/workspace").output;
 } catch (e) {
   console.warn(
     "Angular CLI could not be decorated to enable computation caching. Please ensure @nrwl/workspace is installed."
   );
   process.exit(0);
 }

 /**
  * Symlink of ng to nx, so you can keep using `ng build/test/lint` and still
  * invoke the Nx CLI and get the benefits of computation caching.
  */
 function symlinkNgCLItoNxCLI() {
   try {
     const ngPath = "./node_modules/.bin/ng";
     const nxPath = "./node_modules/.bin/nx";
     if (isWindows) {
       /**
        * This is the most reliable way to create symlink-like behavior on Windows.
        * Such that it works in all shells and works with npx.
        */
       ["", ".cmd", ".ps1"].forEach((ext) => {
         if (fs.existsSync(nxPath + ext))
           fs.writeFileSync(ngPath + ext, fs.readFileSync(nxPath + ext));
       });
     } else {
       // If unix-based, symlink
       cp.execSync(`ln -sf ./nx ${ngPath}`);
     }
   } catch (e) {
     output.error({
       title:
         "Unable to create a symlink from the Angular CLI to the Nx CLI:" +
         e.message,
     });
     throw e;
   }
 }

 try {
   symlinkNgCLItoNxCLI();
   require("@nrwl/cli/lib/decorate-cli").decorateCli();
   output.log({
     title: "Angular CLI has been decorated to enable computation caching.",
   });
 } catch (e) {
   output.error({
     title: "Decoration of the Angular CLI did not complete successfully",
   });
 }