feat: significantly improve CLI startup times

Move a few heavier modules from static imports to lazy `require()`s.
Also remove support for globally installed addons via yarn *and* npm.
If Yarn is detected, Denali will search Yarn for global addons, otherwise
it wills search npm, but not both. This lets Yarn users avoid the
delays that npm forces (because we need to shell out for `npm root`, which
eats 500ms).

We could make this behavior configurable in the future, once we have
a ~/.denali config file

Author: davewasmer

lib/blueprint.ts

@@ -12,7 +12,6 @@ import { execSync, ExecSyncOptions } from 'child_process';
 import { sync as commandExists } from 'command-exists';
 import * as chalk from 'chalk';
 import * as walk from 'walk-sync';
-import * as codeshift from 'jscodeshift';
 import * as mkdirp from 'mkdirp';
 import * as rimraf from 'rimraf';
 import * as yargs from 'yargs';
@@ -330,6 +329,7 @@ export default class Blueprint extends Command {
       ui.warn(`Attempted to add "${ method.toUpperCase() } ${ urlPattern } -> ${ actionPath }" route, but config/routes.js does not exist. Skipping ...`);
       return;
     }
+    const codeshift = require('jscodeshift');
     let j = codeshift;
     let ast = codeshift(routesSource);
     let drawRoutesFunction = ast.find(j.ExportDefaultDeclaration).get().value.declaration;
@@ -377,6 +377,7 @@ export default class Blueprint extends Command {
       ui.warn(`Attempted to remove "${ method.toUpperCase() } ${ urlPattern } -> ${ actionPath }" route, but config/routes.js does not exist. Skipping ...`);
       return;
     }
+    const codeshift = require('jscodeshift');
     let j = codeshift;
     let ast = codeshift(routesSource);
     let drawRoutesFunction = ast.find(j.ExportDefaultDeclaration).get().value.declaration;

lib/find-addons.ts

@@ -38,12 +38,7 @@ export default function findAddons(isLocal: boolean): AddonSummary[] {
     return finalizeAddons(addons);
   }
 
-  let npmRoot = execSync('npm root -g').toString().trim();
-  debug(`searching for addons globally in npm root: ${ npmRoot }`);
-  let addons = findPlugins(merge({
-    dir: npmRoot,
-    scanAllDirs: true
-  }, findOptions));
+  let addons;
 
   // Because yarn stores it's global modules separately, and doesn't yet support the `root` command,
   // we have to double check yarn's global installs for any denali addons. The easiest way of
@@ -52,13 +47,12 @@ export default function findAddons(isLocal: boolean): AddonSummary[] {
   // development of global addons (like denali itself)
   // TODO shell out to `yarn root` once yarnpkg/yarn#2388 is fixed
   if (commandExists('yarn')) {
-    let yarnGlobalInstalls = path.join(YarnConstants.GLOBAL_MODULE_DIRECTORY, 'node_modules');
+    let yarnGlobalInstalls = YarnConstants.GLOBAL_MODULE_DIRECTORY;
     debug(`searching for addons globally in yarn global installs: ${ yarnGlobalInstalls }`);
     if (fs.existsSync(yarnGlobalInstalls)) {
-      addons = addons.concat(findPlugins(merge({
-        dir: yarnGlobalInstalls,
-        scanAllDirs: true
-      }, findOptions)));
+      addons = findPlugins(merge({
+        dir: yarnGlobalInstalls
+      }, findOptions));
     } else {
       debug(`Tried to load globally installed addons from yarn, but ${ yarnGlobalInstalls } doesn't exist, skipping ...`);
     }
@@ -72,6 +66,13 @@ export default function findAddons(isLocal: boolean): AddonSummary[] {
     } else {
       debug(`Tried to load globally linked addons from yarn, but ${ yarnGlobalLinks } doesn't exist, skipping ...`);
     }
+  } else {
+    let npmRoot = execSync('npm root -g').toString().trim();
+    debug(`searching for addons globally in npm root: ${ npmRoot }`);
+    addons = findPlugins(merge({
+      dir: npmRoot,
+      scanAllDirs: true
+    }, findOptions));
   }
 
   return finalizeAddons(addons);

lib/project.ts

@@ -6,8 +6,6 @@ import {
 import * as path from 'path';
 import * as fs from 'fs';
 import * as dedent from 'dedent-js';
-import * as nsp from 'nsp';
-import * as broccoli from 'broccoli';
 import * as rimraf from 'rimraf';
 import printSlowNodes from 'broccoli-slow-trees';
 import { sync as copyDereferenceSync } from 'copy-dereference';
@@ -168,6 +166,7 @@ export default class Project {
       this.rootTree = this.rootBuilder.toTree();
     }
 
+    const broccoli = require('broccoli');
     let broccoliBuilder = this.broccoliBuilder = new broccoli.Builder(this.rootTree);
     // tslint:disable-next-line:completed-docs
     function onExit() {
@@ -314,6 +313,7 @@ export default class Project {
    */
   protected auditPackage() {
     debug('sending package.json to nsp for audit');
+    const nsp = require('nsp');
     let pkg = path.join(this.dir, 'package.json');
     nsp.check({ package: pkg }, (err: any, vulnerabilities: Vulnerability[]) => {
       if (err && [ 'ENOTFOUND', 'ECONNRESET' ].indexOf(err.code) > -1) {