feat(pluginutils): add exactRegex and prefixRegex (#1865)

Author: sapphi-red

packages/pluginutils/README.md

@@ -223,6 +223,22 @@ export default function myPlugin(options = {}) {
 }
 ```
 
+### exactRegex
+
+Constructs a RegExp that matches the exact string specified. This is useful for plugin hook filters.
+
+Parameters: `(str: String, flags?: String)`<br>
+Returns: `RegExp`
+
+#### Usage
+
+```js
+import { exactRegex } from '@rollup/pluginutils';
+
+exactRegex('foobar'); // /^foobar$/
+exactRegex('foo(bar)', 'i'); // /^foo\(bar\)$/i
+```
+
 ### makeLegalIdentifier
 
 Constructs a bundle-safe identifier from a `String`.
@@ -255,6 +271,22 @@ normalizePath('foo\\bar'); // 'foo/bar'
 normalizePath('foo/bar'); // 'foo/bar'
 ```
 
+### prefixRegex
+
+Constructs a RegExp that matches a value that has the specified prefix. This is useful for plugin hook filters.
+
+Parameters: `(str: String, flags?: String)`<br>
+Returns: `RegExp`
+
+#### Usage
+
+```js
+import { prefixRegex } from '@rollup/pluginutils';
+
+prefixRegex('foobar'); // /^foobar/
+prefixRegex('foo(bar)', 'i'); // /^foo\(bar\)/i
+```
+
 ## Meta
 
 [CONTRIBUTING](/.github/CONTRIBUTING.md)

packages/pluginutils/src/filterUtils.ts

@@ -0,0 +1,12 @@
+export function exactRegex(str: string, flags?: string): RegExp {
+  return new RegExp(`^${escapeRegex(str)}$`, flags);
+}
+
+export function prefixRegex(str: string, flags?: string): RegExp {
+  return new RegExp(`^${escapeRegex(str)}`, flags);
+}
+
+const escapeRegexRE = /[-/\\^$*+?.()|[\]{}]/g;
+function escapeRegex(str: string): string {
+  return str.replace(escapeRegexRE, '\\$&');
+}

packages/pluginutils/src/index.ts

@@ -5,15 +5,18 @@ import dataToEsm from './dataToEsm';
 import extractAssignedNames from './extractAssignedNames';
 import makeLegalIdentifier from './makeLegalIdentifier';
 import normalizePath from './normalizePath';
+import { exactRegex, prefixRegex } from './filterUtils';
 
 export {
   addExtension,
   attachScopes,
   createFilter,
   dataToEsm,
+  exactRegex,
   extractAssignedNames,
   makeLegalIdentifier,
-  normalizePath
+  normalizePath,
+  prefixRegex
 };
 
 // TODO: remove this in next major
@@ -22,7 +25,9 @@ export default {
   attachScopes,
   createFilter,
   dataToEsm,
+  exactRegex,
   extractAssignedNames,
   makeLegalIdentifier,
-  normalizePath
+  normalizePath,
+  prefixRegex
 };

packages/pluginutils/test/filterUtils.ts

@@ -0,0 +1,27 @@
+import test from 'ava';
+
+import { exactRegex, prefixRegex } from '../';
+
+test('exactRegex supports without flag parameter', (t) => {
+  t.is(exactRegex('foo').toString(), '/^foo$/');
+});
+
+test('exactRegex supports with flag parameter', (t) => {
+  t.is(exactRegex('foo', 'i').toString(), '/^foo$/i');
+});
+
+test('exactRegex escapes special characters for Regex', (t) => {
+  t.is(exactRegex('foo(bar)').toString(), '/^foo\\(bar\\)$/');
+});
+
+test('prefixRegex supports without flag parameter', (t) => {
+  t.is(prefixRegex('foo').toString(), '/^foo/');
+});
+
+test('prefixRegex supports with flag parameter', (t) => {
+  t.is(prefixRegex('foo', 'i').toString(), '/^foo/i');
+});
+
+test('prefixRegex escapes special characters for Regex', (t) => {
+  t.is(prefixRegex('foo(bar)').toString(), '/^foo\\(bar\\)/');
+});

packages/pluginutils/types/index.d.ts

@@ -62,6 +62,13 @@ export function createFilter(
  */
 export function dataToEsm(data: unknown, options?: DataToEsmOptions): string;
 
+/**
+ * Constructs a RegExp that matches the exact string specified.
+ * @param str the string to match.
+ * @param flags flags for the RegExp.
+ */
+export function exactRegex(str: string, flags?: string): RegExp;
+
 /**
  * Extracts the names of all assignment targets based upon specified patterns.
  * @param param An `acorn` AST Node.
@@ -78,21 +85,32 @@ export function makeLegalIdentifier(str: string): string;
  */
 export function normalizePath(filename: string): string;
 
+/**
+ * Constructs a RegExp that matches a value that has the specified prefix.
+ * @param str the string to match.
+ * @param flags flags for the RegExp.
+ */
+export function prefixRegex(str: string, flags?: string): RegExp;
+
 export type AddExtension = typeof addExtension;
 export type AttachScopes = typeof attachScopes;
 export type CreateFilter = typeof createFilter;
+export type ExactRegex = typeof exactRegex;
 export type ExtractAssignedNames = typeof extractAssignedNames;
 export type MakeLegalIdentifier = typeof makeLegalIdentifier;
 export type NormalizePath = typeof normalizePath;
 export type DataToEsm = typeof dataToEsm;
+export type PrefixRegex = typeof prefixRegex;
 
 declare const defaultExport: {
   addExtension: AddExtension;
   attachScopes: AttachScopes;
   createFilter: CreateFilter;
   dataToEsm: DataToEsm;
+  exactRegex: ExactRegex;
   extractAssignedNames: ExtractAssignedNames;
   makeLegalIdentifier: MakeLegalIdentifier;
   normalizePath: NormalizePath;
+  prefixRegex: PrefixRegex;
 };
 export default defaultExport;