Fix: escape unit separator and del

Author: antonmedv

build/index.cjs

@@ -88,7 +88,7 @@ function parse(source) {
         if (ch === `
 `)
           throw new SyntaxError(errorSnippet());
-        if (ch < "")
+        if (ch < " " || ch === "\x7F")
           throw new SyntaxError(errorSnippet());
         str += ch;
       }

build/index.js

@@ -104,7 +104,7 @@ export function parse(source: string): any {
         break
       } else if ((ch as string) === '\n') {
         throw new SyntaxError(errorSnippet())
-      } else if ((ch as string) < '\x1F') {
+      } else if ((ch as string) < '\x20' || ch === '\x7F') {
         throw new SyntaxError(errorSnippet())
       } else {
         str += ch

build/maml.min.js

@@ -55,4 +55,12 @@ describe('error', () => {
   test('unescaped \u0000 inside string', () => {
     expect(() => parse('"\u0000"')).toThrow('Unexpected character "\\u0000" on line 1.')
   })
+
+  test('unescaped U+001F inside string', () => {
+    expect(() => parse('"\u001F"')).toThrow('on line 1.')
+  })
+
+  test('unescaped U+007F (DEL) inside string', () => {
+    expect(() => parse('"\u007F"')).toThrow('on line 1.')
+  })
 })