fix: fix autocorrections being assigned to the wrong field

src/parse/__tests__/swissDrivingLicense.test.ts

@@ -92,11 +92,11 @@ describe('parse Swiss Driving License', () => {
         { line: 1, column: 24, original: 'G', corrected: '6' },
       ],
       [],
+      [],
       [
         { line: 2, column: 12, original: '8', corrected: 'B' },
         { line: 2, column: 13, original: '1', corrected: 'I' },
       ],
-      [],
     ]);
   });
 });

src/parse/__tests__/td1.test.ts

@@ -191,10 +191,11 @@ describe('parse TD1', () => {
       [
         { line: 2, column: 0, original: '5', corrected: 'S' },
         { line: 2, column: 2, original: '1', corrected: 'I' },
+      ],
+      [
         { line: 2, column: 8, original: '0', corrected: 'O' },
         { line: 2, column: 14, original: '8', corrected: 'B' },
       ],
-      [],
     ]);
   });
 });

src/parse/__tests__/td2.test.ts

@@ -56,9 +56,8 @@ describe('parse TD2', () => {
       [
         { line: 0, column: 9, original: '5', corrected: 'S' },
         { line: 0, column: 10, original: '5', corrected: 'S' },
-        { line: 0, column: 23, original: '1', corrected: 'I' },
       ],
-      [],
+      [{ line: 0, column: 23, original: '1', corrected: 'I' }],
       [],
       [],
       [{ line: 1, column: 12, original: '0', corrected: 'O' }],

src/parse/createFieldParser.ts

@@ -48,10 +48,7 @@ interface Range {
 
 export interface CreateFieldParserResult {
   parser: (lines: string[], autocorrect?: Autocorrect[]) => Details;
-  autocorrector: (lines: string[]) => {
-    correctedLines: string[];
-    autocorrect: Autocorrect[];
-  };
+  autocorrector: (lines: string[]) => Autocorrect[];
 }
 
 export default function createFieldParser(
@@ -113,13 +110,23 @@ export default function createFieldParser(
         result.start = range.start + parsed.start;
         result.end = range.start + parsed.end;
       }
+
+      // We ignore any autocorrect which applied to a character outside of the
+      // field's start / end range.
+      result.autocorrect = result.autocorrect.filter((autoCorrect) => {
+        return (
+          autoCorrect.line === result.line &&
+          autoCorrect.column >= result.start &&
+          autoCorrect.column < result.end
+        );
+      });
     } catch (e: any) {
       result.error = e.message;
     }
+
     return result;
   };
   const autocorrector = (lines: string[]) => {
-    let corrected = lines;
     let source = getText(lines, fieldOptions);
     let autocorrect: Autocorrect[] = [];
     const type = fieldOptions.type || fieldTypes.ALPHANUMERIC;
@@ -128,8 +135,7 @@ export default function createFieldParser(
       source = result.correctedLine;
       autocorrect = result.autocorrect;
     }
-    corrected = changeText(lines, fieldOptions, source);
-    return { correctedLines: corrected, autocorrect };
+    return autocorrect;
   };
   return { parser, autocorrector };
 }
@@ -142,18 +148,6 @@ function getText(
   return line.substring(options.start, options.end);
 }
 
-function changeText(
-  lines: string[],
-  options: Pick<FieldOptions, 'line' | 'end' | 'start'>,
-  text: string,
-) {
-  const line = lines[options.line];
-  const newText =
-    line.substring(0, options.start) + text + line.substring(options.end);
-  lines[options.line] = newText;
-  return lines;
-}
-
 function checkType(
   options: object,
   name: string,

src/parse/getResult.ts

@@ -35,16 +35,24 @@ function getCorrection(
   fieldParsers: CreateFieldParserResult[],
   autocorrect: boolean,
 ) {
-  let corrected = lines;
   const autocorrectArray: Autocorrect[][] = [];
 
   if (autocorrect) {
     fieldParsers.forEach(({ autocorrector }) => {
-      const result = autocorrector(corrected);
-      autocorrectArray.push(result.autocorrect);
-      corrected = result.correctedLines;
+      autocorrectArray.push(autocorrector(lines));
     });
   }
+  // Apply autocorrect on the whole MRZ
+  const corrected = lines.slice();
+  for (let autocorrect of autocorrectArray) {
+    for (let correction of autocorrect) {
+      corrected[correction.line] = setCharAt(
+        corrected[correction.line],
+        correction.column,
+        correction.corrected,
+      );
+    }
+  }
   return { corrected, autocorrectArray };
 }
 export function getResult(
@@ -60,6 +68,7 @@ export function getResult(
     fieldParsers,
     autocorrect,
   );
+
   const details = getDetails(corrected, fieldParsers, autocorrectArray);
   const fields = getFields(details);
   const result = {
@@ -70,3 +79,8 @@ export function getResult(
   };
   return result;
 }
+
+function setCharAt(source: string, index: number, replaceWith: string) {
+  if (index > source.length - 1) return source;
+  return source.substring(0, index) + replaceWith + source.substring(index + 1);
+}