experimental skip npm install

src/index.ts

@@ -4,6 +4,9 @@ import rimraf from 'rimraf';
 import chalk from 'chalk';
 import ora from 'ora';
 import yargs from 'yargs-parser';
+import https from 'https';
+import mkdirp from 'mkdirp';
+import os from 'os';
 
 import * as rollup from 'rollup';
 import rollupPluginNodeResolve from 'rollup-plugin-node-resolve';
@@ -18,9 +21,12 @@ export interface InstallOptions {
   isStrict?: boolean;
   isOptimized?: boolean;
   skipFailures?: boolean;
+  skipNpm?: boolean;
 }
 
 const cwd = process.cwd();
+const cdnUrl = 'https://unpkg.com';
+const cwdManifest = require(path.join(cwd, 'package.json'));
 const banner = chalk.bold(`@pika/web`) + ` installing... `;
 const detectionResults = [];
 let spinner = ora(banner);
@@ -37,7 +43,9 @@ function showHelp() {
 }
 
 function formatDetectionResults(skipFailures): string {
-  return detectionResults.map(([d, yn]) => yn ? chalk.green(d) : skipFailures ? chalk.dim(d) : chalk.red(d)).join(', ');
+  return detectionResults
+    .map(([d, yn]) => (yn ? chalk.green(d) : skipFailures ? chalk.dim(d) : chalk.red(d)))
+    .join(', ');
 }
 
 function logError(msg) {
@@ -46,13 +54,25 @@ function logError(msg) {
   spinner.fail();
 }
 
-
 class ErrorWithHint extends Error {
   constructor(message: string, public readonly hint: string) {
     super(message);
   }
 }
 
+function getDependency(dep: string): string {
+  let [scope, name] = dep.split('/');
+  if (scope.charAt(0) === '@') scope += '/' + name;
+  return scope;
+}
+
+function resolveWebDepFromCDN(dep: string): string {
+  const depFromDeps = getDependency(dep);
+  const deps = cwdManifest.dependencies || {};
+  const version = deps[depFromDeps] ? `@${deps[depFromDeps]}` : '';
+  return `${cdnUrl}/${depFromDeps}${version}?type=module`;
+}
+
 /**
  * Resolve a "webDependencies" input value to the correct absolute file location.
  * Supports both npm package names, and file paths relative to the node_modules directory.
@@ -86,9 +106,7 @@ function resolveWebDependency(dep: string): string {
     return path.join(nodeModulesLoc, manifest.module);
   }
 
-  throw new Error(
-    `Error loading "${dep}" at "${nodeModulesLoc}". (MODE=${dependencyStats.mode}) `,
-  );
+  throw new Error(`Error loading "${dep}" at "${nodeModulesLoc}". (MODE=${dependencyStats.mode}) `);
 }
 
 /**
@@ -99,15 +117,37 @@ function getWebDependencyName(dep: string): string {
   return dep.replace(/\.js$/, '');
 }
 
+function safeWriter(file: string) {
+  file = path.normalize(file);
+  mkdirp.sync(path.dirname(file));
+  return fs.createWriteStream(file);
+}
+
+function download(uri: string, file: string) {
+  return new Promise((res, rej) => {
+    https
+      .get(uri, r => {
+        const code = r.statusCode;
+        if (code >= 400) return rej({code, message: r.statusMessage});
+        if (code > 300 && code < 400) {
+          return download(`${cdnUrl}${r.headers.location}`, file).then(res);
+        }
+        const write = safeWriter(file).on('finish', _ => res(file));
+        r.pipe(write);
+      })
+      .on('error', rej);
+  });
+}
+
 export async function install(
   arrayOfDeps: string[],
-  {isCleanInstall, destLoc, skipFailures, isStrict, isOptimized}: InstallOptions,
+  {isCleanInstall, destLoc, skipFailures, isStrict, isOptimized, skipNpm}: InstallOptions,
 ) {
   if (arrayOfDeps.length === 0) {
     logError('no dependencies found.');
     return;
   }
-  if (!fs.existsSync(path.join(cwd, 'node_modules'))) {
+  if (!fs.existsSync(path.join(cwd, 'node_modules')) && !skipNpm) {
     logError('no "node_modules" directory exists. Did you run "npm install" first?');
     return;
   }
@@ -120,7 +160,7 @@ export async function install(
   for (const dep of arrayOfDeps) {
     try {
       const depName = getWebDependencyName(dep);
-      const depLoc = resolveWebDependency(dep);
+      const depLoc = skipNpm ? resolveWebDepFromCDN(dep) : resolveWebDependency(dep);
       depObject[depName] = depLoc;
       detectionResults.push([dep, true]);
       spinner.text = banner + formatDetectionResults(skipFailures);
@@ -139,23 +179,34 @@ export async function install(
     }
   }
 
+  if (skipNpm) {
+    const promises = [];
+    for (const dep in depObject) {
+      const depPath = path.join(os.tmpdir(), 'pika-web', `${dep}.js`);
+      promises.push(download(depObject[dep], depPath));
+      depObject[dep] = depPath;
+    }
+    await Promise.all(promises);
+  }
+
   const inputOptions = {
     input: depObject,
     plugins: [
       !isStrict &&
         rollupPluginReplace({
           'process.env.NODE_ENV': isOptimized ? '"production"' : '"development"',
         }),
-      rollupPluginNodeResolve({
-        module: true, // Default: true
-        jsnext: false, // Default: false
-        main: !isStrict, // Default: true
-        browser: false, // Default: false
-        modulesOnly: isStrict, // Default: false
-        extensions: ['.mjs', '.js', '.json'], // Default: [ '.mjs', '.js', '.json', '.node' ]
-        // whether to prefer built-in modules (e.g. `fs`, `path`) or local ones with the same names
-        preferBuiltins: false, // Default: true
-      }),
+      !skipNpm &&
+        rollupPluginNodeResolve({
+          module: true, // Default: true
+          jsnext: false, // Default: false
+          main: !isStrict, // Default: true
+          browser: false, // Default: false
+          modulesOnly: isStrict, // Default: false
+          extensions: ['.mjs', '.js', '.json'], // Default: [ '.mjs', '.js', '.json', '.node' ]
+          // whether to prefer built-in modules (e.g. `fs`, `path`) or local ones with the same names
+          preferBuiltins: false, // Default: true
+        }),
       !isStrict &&
         rollupPluginJson({
           preferConst: true,
@@ -181,15 +232,21 @@ export async function install(
 }
 
 export async function cli(args: string[]) {
-  const {help, optimize = false, strict = false, clean = false, dest = 'web_modules'} = yargs(args);
+  const {
+    help,
+    optimize = false,
+    strict = false,
+    clean = false,
+    dest = 'web_modules',
+    skipNpm = false,
+  } = yargs(args);
   const destLoc = path.join(cwd, dest);
 
   if (help) {
     showHelp();
     process.exit(0);
   }
 
-  const cwdManifest = require(path.join(cwd, 'package.json'));
   const doesWhitelistExist = !!(
     cwdManifest['@pika/web'] && cwdManifest['@pika/web'].webDependencies
   );
@@ -204,10 +261,14 @@ export async function cli(args: string[]) {
     skipFailures: !doesWhitelistExist,
     isStrict: strict,
     isOptimized: optimize,
+    skipNpm,
   });
   if (result) {
     spinner.succeed(
-      chalk.bold(`@pika/web`) + ` installed: ` + formatDetectionResults(!doesWhitelistExist) + '. ' +
+      chalk.bold(`@pika/web`) +
+        ` installed: ` +
+        formatDetectionResults(!doesWhitelistExist) +
+        '. ' +
         chalk.dim(`[${((Date.now() - startTime) / 1000).toFixed(2)}s]`),
     );
   }