Check for executability & improve perf in $PATH command detection

Switching to lookpath should speed things up by not actually spawning
anything, and make some of these checks a bit more rigorous.

Author: pimterry

package-lock.json

@@ -37,13 +37,11 @@
     "@oclif/plugin-update": "^1.3.8",
     "@sentry/integrations": "^5.29.2",
     "@sentry/node": "^5.29.2",
-    "@types/command-exists": "^1.2.0",
     "@types/cors": "^2.8.7",
     "@types/node-fetch": "^2.5.4",
     "@types/tmp": "0.0.33",
     "async-mutex": "^0.1.3",
     "chrome-remote-interface": "^0.28.0",
-    "command-exists": "^1.2.8",
     "cors": "^2.8.5",
     "cors-gate": "^1.1.3",
     "env-paths": "^1.0.0",
@@ -54,6 +52,7 @@
     "graphql": "^14.7.0",
     "iconv-lite": "^0.4.24",
     "lodash": "^4.17.21",
+    "lookpath": "^1.2.1",
     "mime-types": "^2.1.27",
     "mockttp": "^1.2.1",
     "node-fetch": "^2.6.1",

package.json

@@ -2,7 +2,7 @@ import { promisify } from 'util';
 import * as fs from 'fs';
 import * as tmp from 'tmp';
 import * as rimraf from 'rimraf';
-import * as ensureCommandExists from 'command-exists';
+import { lookpath } from 'lookpath';
 
 export function delay(durationMs: number): Promise<void> {
     return new Promise((resolve) => setTimeout(resolve, durationMs));
@@ -63,7 +63,7 @@ export const ensureDirectoryExists = (path: string) =>
     checkAccess(path).catch(() => mkDir(path, { recursive: true }));
 
 export const commandExists = (path: string): Promise<boolean> =>
-    ensureCommandExists(path).then(() => true).catch(() => false);
+    lookpath(path).then((result) => result !== undefined);
 
 export const createTmp = (options: tmp.Options = {}) => new Promise<{
     path: string,