UI

[inverse-tax] / tax_ui.js

diff --git a/tax_ui.js b/tax_ui.js
new file mode 100644 (file)
index 0000000..4f2b625
--- /dev/null
+++ b/tax_ui.js
@@ -0,0 +1,24 @@
+function load_tax_table(table_id, deductible_id) {
+  return apply_deductible(parse_tax_table(document.getElementById(table_id).value),
+                          parseFloat(document.getElementById(deductible_id).value));
+}
+
+function format_number(n) {
+  return n.toLocaleString('en', {useGrouping:true, style: 'currency', currency: 'USD'});
+}
+
+function calculate() {
+  const table1 = load_tax_table('tax_table_1', 'deductible_1');
+  const table2 = load_tax_table('tax_table_2', 'deductible_2');
+  const after_tax = parseFloat(document.getElementById('after_tax').value);
+
+  const before_tax = invert(merge_tax_tables(table1, table2))(after_tax);
+
+  const tax1 = tax(table1, before_tax);
+  const tax2 = tax(table2, before_tax);
+
+  document.getElementById('before_tax').textContent = format_number(before_tax);
+  document.getElementById('tax_1').textContent = format_number(tax1);
+  document.getElementById('tax_2').textContent = format_number(tax2);
+  document.getElementById('after_tax_verification').textContent = format_number(before_tax - (tax1 + tax2));
+}