Grunt won't install on my project - npm

Question

I've been trying to install grunt on my project but no luck.
Here's the error i get when running npm install
npm WARN package.json XXX#1.0.0 No license field.
npm ERR! Windows_NT 6.1.7601
npm ERR! argv "C:\\Program Files\\nodejs\\\\node.exe" "C:\\Program Files\\nodejs\\node_modules\\npm\\bin\\npm-cli.js" "install"
npm ERR! node v0.12.7
npm ERR! npm v2.11.3
npm ERR! code EPEERINVALID
npm ERR! peerinvalid The package grunt does not satisfy its siblings' peerDependencies requirements!
npm ERR! peerinvalid Peer grunt-contrib-copy#0.8.2 wants grunt#>=0.4.0
npm ERR! peerinvalid Peer grunt-contrib-sass#0.9.2 wants grunt#>=0.4.0
npm ERR! peerinvalid Peer grunt-contrib-watch#0.6.1 wants grunt#~0.4.0
npm ERR! peerinvalid Peer grunt-mustache-render#1.9.0 wants grunt#^0.4.5
Heres' what my package json looks like
{
"name": "XXX",
"version": "1.0.0",
"repository": {
"type": "git",
"url": "some git repo"
},
"devDependencies": {
"grunt-html-build": "^0.5.1",
"grunt-contrib-copy": "^0.8.0",
"grunt-contrib-sass": "^0.9.2",
"grunt-contrib-watch": "^0.6.1",
"grunt-mustache-render": "^1.9.0"
}
}
I've tried npm update -g but nothing much seems to happen.
npm --version says 2.11.3
the only relevant error i think i found was when i ran
> npm list
├─┬ grunt#1.0.1 peer invalid
and at the end: npm ERR! peer invalid: grunt#1.0.1
> grunt --version
grunt-cli v1.2.0
grunt v1.0.1
do i need to re-install grunt or something ? I haven't found a command for that.
Thanks for your help!

Answer 1

Some grunt-plugins haven't updated their peer dependency requirements yet to work with the 1.0 version of grunt (1.0 is fairly new). You can try to remove the peer dependency requirements, but that could be problematic depending on what changes were made between 0.4.5 and 1.0. (0.4.5 was the last version prior to 1.0)
Try installing the version of grunt that's compatible with the plugins first: npm install grunt#^0.4.5 --save-dev

Answer 2

For npm version 2, you should have grunt version 0.4.5
"devDependencies": {
"grunt": "^0.4.5" }
As you seen below , npm version is less than 3 so you should have grunt version: ^0.4.5
$ npm --version
2.15.11

Answer 3

Output from npm install explains everything pretty good:
npm ERR! peerinvalid Peer grunt-contrib-copy#0.8.2 wants grunt#>=0.4.0
npm ERR! peerinvalid Peer grunt-contrib-sass#0.9.2 wants grunt#>=0.4.0
npm ERR! peerinvalid Peer grunt-contrib-watch#0.6.1 wants grunt#~0.4.0
npm ERR! peerinvalid Peer grunt-mustache-render#1.9.0 wants grunt#^0.4.5
To understand it you need to understand semantical versioning explained here:
https://docs.npmjs.com/files/package.json#version
and here
https://docs.npmjs.com/misc/semver
In order to fix the problem you must specify more flexible version number for packages that block installation of new grunt.
Just set ">= 0.0.0" requirement for all grunt plugins and their versions will be synchronized with grunt version by npm.
"devDependencies": {
"grunt-html-build": ">=0.0.0",
"grunt-contrib-copy": ">=0.0.0",
"grunt-contrib-sass": ">=0.0.0",
"grunt-contrib-watch": ">=0.0.0",
"grunt-mustache-render": ">=0.0.0"
}