Add find_unused_deps monorepo script

packages/monorepo-scripts/src/find_unused_dependencies.ts

@@ -0,0 +1,44 @@
+#!/usr/bin/env node
+
+import * as depcheck from 'depcheck';
+import * as fs from 'fs';
+import lernaGetPackages = require('lerna-get-packages');
+import * as _ from 'lodash';
+import { exec as execAsync } from 'promisify-child-process';
+
+import { constants } from './constants';
+import { utils } from './utils';
+
+const IGNORE_PACKAGES = ['@0xproject/deployer'];
+
+(async () => {
+    utils.log('*** NOTE: Not all deps listed here are actually not required. ***');
+    utils.log("*** `depcheck` isn't perfect so double check before actually removing any. ***\n");
+    const lernaPackages = lernaGetPackages(constants.monorepoRootPath);
+    for (const lernaPackage of lernaPackages) {
+        if (_.includes(IGNORE_PACKAGES, lernaPackage.package.name)) {
+            continue; // skip
+        }
+        utils.log(`Checking ${lernaPackage.package.name} for unused deps. This might take a while...`);
+
+        const configs = {};
+        const result: any = await depcheckAsync(lernaPackage.location, configs);
+        if (!_.isEmpty(result.dependencies)) {
+            _.each(result.dependencies, dep => {
+                utils.log(dep);
+            });
+        }
+        utils.log('\n');
+    }
+})().catch(err => {
+    utils.log(err);
+    process.exit(1);
+});
+
+async function depcheckAsync(path: string, opts: any) {
+    return new Promise<void>((resolve, reject) => {
+        depcheck(path, opts, (unused: any) => {
+            resolve(unused);
+        });
+    });
+}