feat: create validateMrzChecksum method

packages/mrtd/src/models/MrzData.ts

@@ -4,3 +4,55 @@ export type MrzData = {
   raw: string | string[]
   parsed: { format?: Mrz.MRZFormat; fields: Partial<Record<Mrz.FieldName, string | null>>; valid: boolean }
 }
+
+export function validateMrzChecksum(line: string): boolean {
+  const charValues: { [key: string]: number } = {
+    A: 10,
+    B: 11,
+    C: 12,
+    D: 13,
+    E: 14,
+    F: 15,
+    G: 16,
+    H: 17,
+    I: 18,
+    J: 19,
+    K: 20,
+    L: 21,
+    M: 22,
+    N: 23,
+    O: 24,
+    P: 25,
+    Q: 26,
+    R: 27,
+    S: 28,
+    T: 29,
+    U: 30,
+    V: 31,
+    W: 32,
+    X: 33,
+    Y: 34,
+    Z: 35,
+  }
+
+  const weights = [7, 3, 1]
+  const checkDigit = parseInt(line.slice(-1))
+  const lineToValidate = line.slice(0, -1)
+
+  const total = lineToValidate.split('').reduce((acc, char, index) => {
+    let value: number
+    if (/\d/.test(char)) {
+      value = parseInt(char)
+    } else if (/[A-Z]/.test(char)) {
+      value = charValues[char]
+    } else if (char === '<') {
+      value = 0
+    } else {
+      return acc
+    }
+
+    return acc + value * weights[index % 3]
+  }, 0)
+
+  return total % 10 === checkDigit
+}