Why is gulp-watch not installing?

Question

Node.js

I'm trying to install gulp-watch. Not installed. Outputs:

package.json

{
  "name": "project",
  "version": "2.9.0",
  "main": "gulpfile.js",
  "author": "author",
  "license": "ISC",
  "devDependencies": {
    "browser-sync": "^2.10.0",
    "gulp": "^3.9.0",
    "gulp-autoprefixer": "^3.1.0",
    "gulp-concat": "^2.6.0",
    "gulp-csscomb": "^3.0.6",
    "gulp-csso": "^1.0.1",
    "gulp-image-optimization": "^0.1.3",
    "gulp-plumber": "^1.0.1",
    "gulp-sass": "^2.1.0",
    "gulp-tinypng": "^1.0.2",
    "gulp-uglify": "^1.4.2",
    "gulp.spritesmith": "^4.3.0",
    "merge-stream": "^1.0.0",
  },
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "description": ""
}

What's wrong?
Win 8.1
node v4.2.4
npm v2.14.12

Answer 1

it is also written there) not a valid package.json on line 21

Answer 2

I can't install gulp it says error help , thanks in advance :
C:\Users\Yuri>npm install gulp -g
npm ERR! C:\Users\Yuri\AppData\Roaming\npm-cache\_cacache is not a legal HTTP he
ader value
npm ERR! A complete log of this run can be found in:
npm ERR! C:\Users\Yuri\AppData\Roaming\npm-cache\_logs\2017-08-03T19_03_36_4
01Z-debug.log