{
  "name": "gzblogs",
  "version": "1.0.0",
  "description": "An ASP.NET Core application for getting started with Less",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "private": true,
  "keywords": [
    "aspnetcore",
    "less"
  ],
  "author": "anuraj",
  "license": "MIT",
  "devDependencies": {
    "gulp": "3.9.1",
    "gulp-less": "3.3.2",
    "gulp-clean-css": "3.9.0"
  }
}

var gulp = require("gulp"),
    cleanCss = require("gulp-clean-css"),
    less = require("gulp-less");

gulp.task("default", function () {
    return gulp.src(‘wwwroot/less/*.less‘)
        .pipe(less())
        .pipe(cleanCss({ compatibility:  ‘ie8‘ }))
        .pipe(gulp.dest(‘wwwroot/css‘));
});

 <Target Name="PreBuild" BeforeTargets="PreBuildEvent">
    <Exec WorkingDirectory="$(ProjectDir)" Command="node_modules\.bin\gulp" />
  </Target>