Cant build app using npx grunt on Windows - node.js

Question

On Windows 8.1 installed Node.js 12.16.
First I run "npm install grunt" in a root directory of project.
Installation passed succesfully, however with the following warnings:
npm WARN read-shrinkwrap This version of npm is compatible with lockfileVersion#
1, but npm-shrinkwrap.json was generated for lockfileVersion#0. I'll try to do m
y best with it!
npm WARN deprecated minimatch#0.2.14: Please update to minimatch 3.0.2 or higher
to avoid a RegExp DoS issue
npm WARN deprecated coffee-script#1.3.3: CoffeeScript on NPM has moved to "coffe
escript" (no hyphen)
npm WARN deprecated minimatch#0.3.0: Please update to minimatch 3.0.2 or higher
to avoid a RegExp DoS issue
npm WARN platform-web#0.0.1 No repository field.
npm WARN platform-web#0.0.1 No license field.
npm WARN The package time-grunt is included as both a dev and production depende
ncy.
npm WARN The package object-assign is included as both a dev and production depe
ndency.
+ grunt#0.4.5
added 38 packages from 47 contributors and audited 54 packages in 3.026s
found 25 vulnerabilities (5 low, 6 moderate, 14 high)
run `npm audit fix` to fix them, or `npm audit` for details
Root directory containts grunt-folder (root_dir/grunt), in which Gruntfile.js and package.json files are located.
And this grunt-folder containts other grunt-folder (root_dir/grunt/grunt). This second grunt containts some js-files.
Then in "root_dir/grunt" I run "npx grunt". But the build aborted with the following log:
>> Local Npm module "grunt-contrib-clean" not found. Is it installed?
>> Local Npm module "grunt-contrib-copy" not found. Is it installed?
>> Local Npm module "grunt-includes" not found. Is it installed?
>> Local Npm module "grunt-text-replace" not found. Is it installed?
>> Local Npm module "grunt-contrib-concat" not found. Is it installed?
>> Local Npm module "grunt-contrib-uglify" not found. Is it installed?
>> Local Npm module "grunt-contrib-cssmin" not found. Is it installed?
>> Local Npm module "grunt-file-creator" not found. Is it installed?
>> Local Npm module "grunt-war" not found. Is it installed?
>> Local Npm module "nexus-deployer" not found. Is it installed?
Warning: Task "clean:all" not found. Use --force to continue.
Aborted due to warnings.
package.json is
{
"name": "platform-web",
"version": "0.0.1",
"description": "Platform",
"devDependencies": {
"archiver": "^0.12.0",
"grunt": "^0.4.5",
"grunt-contrib-clean": "^0.6.0",
"grunt-contrib-concat": "^0.5.1",
"grunt-contrib-copy": "^0.8.0",
"grunt-contrib-cssmin": "0.12.3",
"grunt-contrib-uglify": "^0.6.0",
"grunt-file-creator": "^0.1.3",
"grunt-includes": "^0.5.1",
"grunt-text-replace": "^0.4.0",
"grunt-war": "^0.5.1",
"nexus-deployer": "^0.1.8",
"object-assign": "^4.0.1",
"time-grunt": "^1.1.0"
},
"dependencies": {
"time-grunt": "^1.0.0",
"object-assign": "^4.0.1"
}
}
What am I doing wrong?
p.s.: root-folder is:

Answer 1

Following is only needed for older versions of grunt. New one install the bunstubbs correctly so you can still install grunt via npm and not globally.
Install grunt-cli. This will correctly pick up whichever version of grunt the project is running and execute it.
npm install grunt-cli --save-dev
In the package.json change dev script to
"scripts": {
"start": "npx grunt-cli"
}
then run
npm run start