SPFX compile specific webparts

gulpfile.js

'use strict';

const gulp = require('gulp');
const build = require('@microsoft/sp-build-web');
const coreBuild = require('@microsoft/sp-build-core-tasks');
const OptimizedWebpackTask = require('./OptimizedWebpackTask');
build.addSuppression(`Warning - [sass] The local CSS class 'ms-Grid' is not camelCase and will not be type-safe.`);

build.tslint.enabled = false;

coreBuild.configureWebpack = new OptimizedWebpackTask();

build.initialize(gulp);

OptimizedWebpackTask.js

const ConfigureWebpackTask = require('@microsoft/sp-build-core-tasks/lib/configureWebpack/ConfigureWebpackTask').ConfigureWebpackTask;

class OptimizedWebpackTask extends ConfigureWebpackTask {
  constructor() {
    super(...arguments);
  }

  executeTask(gulp, completeCallback) {
    const script = this.buildConfig.args._[0];
    const webpart = this.buildConfig.args.webpart;

    if (script === 'serve' && webpart) {
      let bundleToCompile = this.properties.bundles[webpart];

      if (!bundleToCompile) {
        throw new Error("Webpart could not be found");
      }

      if (Object.keys(this.properties.bundles).length !== 1) {
        this.properties.bundles = {
          [webpart]: bundleToCompile
        };
      }

    }

    return super.executeTask(gulp, completeCallback);
  }
}

module.exports = OptimizedWebpackTask;