1 files changed, 125 insertions, 0 deletions
diff --git a/index.js b/index.js
new file mode 100644
index 0000000..be7bf61
--- /dev/null
+++ b/index.js
@@ -0,0 +1,125 @@
+module.exports = {
+    parse: parse,
+    validate: validate,
+    parseDateOfBirth: parseDateOfBirth,
+    parseIsMale: parseIsMale,
+    parseIsFemale: parseIsFemale,
+    parseIsSouthAfricanCitizen: parseIsSouthAfricanCitizen
+};
+
+function parse(idNumber) {
+    if (typeof(idNumber) !== 'string') {
+        return undefined;
+    }
+
+    var isValid = validate(idNumber);
+    if (!isValid) {
+        return {
+            valid: false
+        };
+    }
+
+    return {
+        isValid: isValid,
+        dateOfBirth: parseDateOfBirth(idNumber),
+        isMale: parseIsMale(idNumber),
+        isFemale: parseIsFemale(idNumber),
+        isSouthAfricanCitizen: parseIsSouthAfricanCitizen(idNumber)
+    };
+}
+
+function validate(idNumber) {
+    if (!regexpValidate(idNumber) || !datePartValidate(idNumber) || !controlDigitValidate(idNumber)) {
+        return false;
+    }
+
+    return true;
+}
+
+function regexpValidate(idNumber) {
+    if (typeof(idNumber) !== 'string') {
+        return false;
+    }
+    var regexp = /^[0-9]{13}$/;
+    return regexp.test(idNumber);
+}
+
+function datePartValidate(idNumber) {
+    var dateOfBirth = parseDateOfBirth(idNumber);
+    return !!dateOfBirth;
+}
+
+function controlDigitValidate(idNumber) {
+    var checkDigit = parseInt(idNumber[idNumber.length - 1], 10);
+
+    var oddDigitsSum = 0;
+
+    for (var i = 0; i < idNumber.length - 1; i+=2) {
+        oddDigitsSum += parseInt(idNumber[i], 10);
+    }
+    var evenDigits = '';
+    for (var j = 1; j < idNumber.length - 1; j+=2) {
+        evenDigits += idNumber[j];
+    }
+    evenDigits = parseInt(evenDigits, 10);
+    evenDigits *= 2;
+    evenDigits = '' + evenDigits;
+
+    var sumOfEvenDigits = 0;
+    for (var k = 0; k < evenDigits.length; k++) {
+        sumOfEvenDigits += parseInt(evenDigits[k], 10);
+    }
+    var total = sumOfEvenDigits + oddDigitsSum;
+    var computedCheckDigit = 10 - (total % 10);
+
+    if (computedCheckDigit === 10) {
+        computedCheckDigit = 0;
+    }
+    return computedCheckDigit === checkDigit;
+}
+
+function parseDateOfBirth(idNumber) {
+    if (!regexpValidate(idNumber)) {
+        return undefined;
+    }
+
+    //get year, and assume century
+    var currentYear = new Date().getFullYear();
+    var currentCentury = Math.floor(currentYear/100)*100;
+    var yearPart = currentCentury + Number(idNumber.substring(0,2));
+    if (yearPart > currentYear) {
+        yearPart -= 100; //must be last century
+    }
+    
+    //In Javascript, Jan=0. In ID Numbers, Jan=1.
+    var monthPart = Number(idNumber.substring(2,4))-1;
+
+    var dayPart = Number(idNumber.substring(4,6));
+
+    var dateOfBirth = new Date(yearPart, monthPart, dayPart);
+
+    //validate that date is in a valid range by making sure that it wasn't 'corrected' during construction
+    if (!dateOfBirth || dateOfBirth.getFullYear() !== yearPart || dateOfBirth.getMonth() !== monthPart || dateOfBirth.getDate() !== dayPart) {
+        return undefined;
+    }
+    
+    return dateOfBirth;
+}
+
+function parseIsMale(idNumber) {
+    return !parseIsFemale(idNumber);
+}
+
+function parseIsFemale(idNumber) {
+    if (!regexpValidate(idNumber)) {
+        return undefined;
+    }
+    return Number(idNumber[6]) <= 4;
+}
+
+function parseIsSouthAfricanCitizen(idNumber) {
+    if (!regexpValidate(idNumber)) {
+        return undefined;
+    }
+    return Number(idNumber[6]) === 0;
+}