feat: export RegExpSyntaxError

src/index.ts

@@ -2,8 +2,9 @@ import * as AST from "./ast"
 import { RegExpParser } from "./parser"
 import { RegExpValidator } from "./validator"
 import { RegExpVisitor } from "./visitor"
+import { RegExpSyntaxError } from "./regexp-syntax-error"
 
-export { AST, RegExpParser, RegExpValidator }
+export { AST, RegExpParser, RegExpValidator, RegExpSyntaxError }
 
 /**
  * Parse a given regular expression literal then make AST object.

src/regexp-syntax-error.ts

@@ -3,27 +3,34 @@ import type { RegExpValidatorSourceContext } from "./validator"
 export class RegExpSyntaxError extends SyntaxError {
     public index: number
 
-    public constructor(
-        srcCtx: RegExpValidatorSourceContext,
-        flags: { unicode: boolean; unicodeSets: boolean },
-        index: number,
-        message: string,
-    ) {
-        let source = ""
-        if (srcCtx.kind === "literal") {
-            const literal = srcCtx.source.slice(srcCtx.start, srcCtx.end)
-            if (literal) {
-                source = `: ${literal}`
-            }
-        } else if (srcCtx.kind === "pattern") {
-            const pattern = srcCtx.source.slice(srcCtx.start, srcCtx.end)
-            const flagsText = `${flags.unicode ? "u" : ""}${
-                flags.unicodeSets ? "v" : ""
-            }`
-            source = `: /${pattern}/${flagsText}`
-        }
-
-        super(`Invalid regular expression${source}: ${message}`)
+    public constructor(message: string, index: number) {
+        super(message)
         this.index = index
     }
 }
+
+export function newRegExpSyntaxError(
+    srcCtx: RegExpValidatorSourceContext,
+    flags: { unicode: boolean; unicodeSets: boolean },
+    index: number,
+    message: string,
+): RegExpSyntaxError {
+    let source = ""
+    if (srcCtx.kind === "literal") {
+        const literal = srcCtx.source.slice(srcCtx.start, srcCtx.end)
+        if (literal) {
+            source = `: ${literal}`
+        }
+    } else if (srcCtx.kind === "pattern") {
+        const pattern = srcCtx.source.slice(srcCtx.start, srcCtx.end)
+        const flagsText = `${flags.unicode ? "u" : ""}${
+            flags.unicodeSets ? "v" : ""
+        }`
+        source = `: /${pattern}/${flagsText}`
+    }
+
+    return new RegExpSyntaxError(
+        `Invalid regular expression${source}: ${message}`,
+        index,
+    )
+}

src/validator.ts

@@ -1,7 +1,7 @@
 import type { EcmaVersion } from "./ecma-versions"
 import { latestEcmaVersion } from "./ecma-versions"
 import { Reader } from "./reader"
-import { RegExpSyntaxError } from "./regexp-syntax-error"
+import { newRegExpSyntaxError } from "./regexp-syntax-error"
 import {
     ASTERISK,
     BACKSPACE,
@@ -1246,7 +1246,7 @@ export class RegExpValidator {
         message: string,
         context?: { index?: number; unicode?: boolean; unicodeSets?: boolean },
     ): never {
-        throw new RegExpSyntaxError(
+        throw newRegExpSyntaxError(
             this._srcCtx!,
             {
                 unicode: