feat: custom fill char

src/acorn.ts

@@ -8,14 +8,15 @@ import type { StripLiteralOptions } from './types'
  * Will throw error if the input is not valid JavaScript.
  */
 export function _stripLiteralAcorn(code: string, options?: StripLiteralOptions) {
-  const FILL = ' '
+  const FILL = options?.fillChar ?? ' '
+  const FILL_COMMENT = ' '
   let result = ''
 
   const filter = options?.filter ?? (() => true)
 
   function fillupTo(index: number) {
     if (index > result.length)
-      result += code.slice(result.length, index).replace(/[^\n]/g, FILL)
+      result += code.slice(result.length, index).replace(/[^\n]/g, FILL_COMMENT)
   }
 
   const tokens: Token[] = []

src/regex.ts

@@ -15,11 +15,13 @@ const quotesRE = [
  * But will have some caveats on distinguish strings and comments.
  */
 export function stripLiteralRegex(code: string, options?: StripLiteralOptions) {
+  const FILL_COMMENT = ' '
+  const FILL = options?.fillChar ?? ' '
   const filter = options?.filter ?? (() => true)
 
   code = code
-    .replace(multilineCommentsRE, s => filter(s) ? ' '.repeat(s.length) : s)
-    .replace(singlelineCommentsRE, s => filter(s) ? ' '.repeat(s.length) : s)
+    .replace(multilineCommentsRE, s => filter(s) ? FILL_COMMENT.repeat(s.length) : s)
+    .replace(singlelineCommentsRE, s => filter(s) ? FILL_COMMENT.repeat(s.length) : s)
 
   let expanded = code
   // Recursively replace ${} to support nested constructs (e.g. ${`${x}`})
@@ -35,8 +37,8 @@ export function stripLiteralRegex(code: string, options?: StripLiteralOptions) {
       .replace(re, (s, quote, body, index) => {
         if (!filter(s.slice(1, -1)))
           return s
-        code = code.slice(0, index + 1) + ' '.repeat(s.length - 2) + code.slice(index + s.length - 1)
-        return quote + ' '.repeat(s.length - 2) + quote
+        code = code.slice(0, index + 1) + FILL.repeat(s.length - 2) + code.slice(index + s.length - 1)
+        return quote + FILL.repeat(s.length - 2) + quote
       })
   })
 

src/types.ts

@@ -3,4 +3,12 @@ export interface StripLiteralOptions {
    * Will be called for each string literal. Return false to skip stripping.
    */
   filter?: (s: string) => boolean
+
+  /**
+   * Fill the stripped literal with this character.
+   * It must be a single character.
+   *
+   * @default ' '
+   */
+  fillChar?: string
 }

test/custom-fill.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from 'vitest'
+import { executeWithVerify } from './utils'
+
+describe('custom-fill', () => {
+  it('acorn', () => {
+    const result = executeWithVerify(`
+// comment1
+const a = 'aaaa'
+/* comment2 */
+const b = "bbbb"
+
+const c = \`aaaa\${foo}dddd\${bar}\`
+      `.trim(),
+    false,
+    {
+      fillChar: '-',
+      filter: s => s !== 'aaaa',
+    })
+
+    expect(result).toMatchInlineSnapshot(`
+      "// mode: acorn
+                 
+      const a = 'aaaa'
+                    
+      const b = \\"----\\"
+
+      const c = \`aaaa\${foo}----\${bar}\`"
+    `)
+  })
+
+  it('regex', () => {
+    const result = executeWithVerify(`
+\\
+// comment1
+const a = 'aaaa'
+/* comment2 */
+const b = "bbbb"
+
+const c = \`aaaa\${foo}dddd\${bar}\`
+      `.trim(),
+    false,
+    {
+      fillChar: '-',
+      filter: s => s !== 'aaaa',
+    })
+
+    expect(result).toMatchInlineSnapshot(`
+      "// mode: regex
+      \\\\             const a = 'aaaa'
+                    
+      const b = \\"----\\"
+
+      const c = \`aaaa\${foo}----\${bar}\`"
+    `)
+  })
+})

test/utils.ts

@@ -12,9 +12,11 @@ export function executeWithVerify(code: string, verifyAst = true, options?: Stri
 
   const stripped = result.result
 
-  for (let i = 0; i < stripped.length; i++) {
-    if (!stripped[i].match(/\s/))
-      expect(stripped[i]).toBe(code[i])
+  if (!options?.fillChar) {
+    for (let i = 0; i < stripped.length; i++) {
+      if (!stripped[i].match(/\s/))
+        expect(stripped[i]).toBe(code[i])
+    }
   }
 
   expect(stripped.length).toBe(code.length)