ast: replace requires and inits for uglify with terser

Given that uglify is initialised with options, then replace its require and usage with terser

Author: abenezerabebe

packages/migrate/uglifyJsPlugin/__snapshots__/uglifyJsPlugin.test.js.snap

@@ -10,13 +10,13 @@ exports[`uglifyJsPlugin transforms correctly using "uglifyJsPlugin-0" data 1`] =
 `;
 
 exports[`uglifyJsPlugin transforms correctly using "uglifyJsPlugin-1" data 1`] = `
-"const UglifyJsPlugin  = require('uglifyjs-webpack-plugin');
+"const TerserPlugin = require('terser-webpack-plugin');
 module.exports = {
     devtool: \\"source-map\\",
     optimization: {
         minimize: true,
 
-        minimizer: [new UglifyJsPlugin({
+        minimizer: [new TerserPlugin({
             sourceMap: true,
             compress: {}
         })]
@@ -26,13 +26,13 @@ module.exports = {
 `;
 
 exports[`uglifyJsPlugin transforms correctly using "uglifyJsPlugin-2" data 1`] = `
-"const Uglify  = require('uglifyjs-webpack-plugin');
+"const TerserPlugin = require('terser-webpack-plugin');
 module.exports = {
     devtool: \\"source-map\\",
     optimization: {
         minimize: true,
 
-        minimizer: [new Uglify({
+        minimizer: [new TerserPlugin({
             sourceMap: true,
             compress: {}
         })]

packages/migrate/uglifyJsPlugin/uglifyJsPlugin.ts

@@ -67,14 +67,17 @@ export default function(j: IJSCodeshift, ast: INode): INode {
 			* - add require for terser-webpack-plugin
 			* - add to minimizer
 			*/
-				if (pluginVariableAssignment && pluginVariableAssignment.includes("webpack")) {
+				if (pluginVariableAssignment) {
+					// remove require for uglify-js-plugin
+					searchForRequirePlugin.remove();
+
 					// create require for terser-webpack-plugin
 					const pathRequire: INode = getRequire(
 						j,
 						"TerserPlugin",
 						"terser-webpack-plugin",
 					);
-					// append to source code.
+					// prepend to source code.
 					ast
 						.find(j.Program)
 						.replaceWith((p: INode): INode =>