gulpfile.js

/// <binding ProjectOpened='default' />
//
const { watch, src, dest } = require('gulp');
var config = require('./paths.json');

/*
 * app_plugin and build script.
 */

const appPluginPath = '/App_Plugins/' + config.pluginFolder;

const appPlugin = {
    source : config.library + appPluginPath + '/**/*',
    src : config.library + appPluginPath + '/',
    dest : config.site + appPluginPath
}


/*
 * Copys files from app_plugins folder in a library
 * project into a test site.
 * 
 * Your paths.config should look like: 
 * 
 * {
 *    "library": "myPackage.LibraryName",
 *    "pluginFolder": "MyPackageFolder",
 *    "site" : "../Sandbox.Site"
 * }
 * 
 * This will run in the background, so you don't need
 * to rebuild your project when working on script files.
 */

function copy(path, baseFolder, target) {

    return src(path, { base: baseFolder })
        .pipe(dest(target));
}


function watchAppPlugins() {

    watch(appPlugin.source, { ignoreInitial: false })
        .on('change', function (path, stats) {
            copy(path, appPlugin.src, config.site + appPluginPath)
            copy(path, appPlugin.src, config.site + "V9" + appPluginPath)
            copy(path, appPlugin.src, config.site + "V10" + appPluginPath)
        })
        .on('add', function (path, stats) {
            copy(path, appPlugin.src, config.site + appPluginPath)
            copy(path, appPlugin.src, config.site + "V9" + appPluginPath)
            copy(path, appPlugin.src, config.site + "V10" + appPluginPath)
        });
}

exports.default = function () {
    watchAppPlugins();
};