add blank-line-removal plugin

Author: lobsterkatie

rollup/npmHelpers.js

@@ -10,6 +10,7 @@ import deepMerge from 'deepmerge';
 import {
   makeConstToVarPlugin,
   makeNodeResolvePlugin,
+  makeRemoveBlankLinesPlugin,
   makeRemoveESLintCommentsPlugin,
   makeSucrasePlugin,
 } from './plugins/index.js';
@@ -28,6 +29,7 @@ export function makeBaseNPMConfig(options = {}) {
   const sucrasePlugin = makeSucrasePlugin();
   const constToVarPlugin = makeConstToVarPlugin();
   const removeESLintCommentsPlugin = makeRemoveESLintCommentsPlugin();
+  const removeBlankLinesPlugin = makeRemoveBlankLinesPlugin();
 
   return {
     input: entrypoints,
@@ -68,7 +70,7 @@ export function makeBaseNPMConfig(options = {}) {
       interop: esModuleInterop ? 'auto' : 'esModule',
     },
 
-    plugins: [nodeResolvePlugin, sucrasePlugin, constToVarPlugin, removeESLintCommentsPlugin],
+    plugins: [nodeResolvePlugin, sucrasePlugin, constToVarPlugin, removeESLintCommentsPlugin, removeBlankLinesPlugin],
 
     // don't include imported modules from outside the package in the final output
     external: [

rollup/plugins/npmPlugins.js

@@ -81,3 +81,19 @@ export function makeRemoveESLintCommentsPlugin() {
     ],
   });
 }
+
+/**
+ * Create a plugin to strip multiple consecutive blank lines, with or without whitespace in them. from the output.
+ *
+ * @returns A `rollup-plugin-re` instance.
+ */
+export function makeRemoveBlankLinesPlugin() {
+  return regexReplace({
+    patterns: [
+      {
+        test: /\n(\n\s*)+\n/g,
+        replace: '\n\n',
+      },
+    ],
+  });
+}