fix: currency precision formatter (#21293)

cypress/integration/control_currency.js

@@ -0,0 +1,74 @@
+context("Control Currency", () => {
+	const fieldname = "currency_field";
+
+	before(() => {
+		cy.login();
+		cy.visit("/app/website");
+	});
+
+	function get_dialog_with_currency(df_options = {}) {
+		return cy.dialog({
+			title: "Currency Check",
+			fields: [
+				{
+					fieldname: fieldname,
+					fieldtype: "Currency",
+					Label: "Currency",
+					...df_options,
+				},
+			],
+		});
+	}
+
+	it("check value changes", () => {
+		const TEST_CASES = [
+			{
+				input: "10.101",
+				df_options: { precision: 1 },
+				blur_expected: "10.1",
+			},
+			{
+				input: "10.101",
+				df_options: { precision: "3" },
+				blur_expected: "10.101",
+			},
+			{
+				input: "10.101",
+				df_options: { precision: "" }, // default assumed to be 2;
+				blur_expected: "10.10",
+			},
+			{
+				input: "10.101",
+				df_options: { precision: "0" },
+				blur_expected: "10",
+			},
+			{
+				input: "10.101",
+				df_options: { precision: 0 },
+				blur_expected: "10",
+			},
+			{
+				input: "10.101",
+				df_options: { precision: "" },
+				blur_expected: "10.1",
+				default_precision: 1,
+			},
+		];
+
+		TEST_CASES.forEach((test_case) => {
+			cy.window()
+				.its("frappe")
+				.then((frappe) => {
+					frappe.boot.sysdefaults.currency = test_case.currency;
+					frappe.boot.sysdefaults.currency_precision = test_case.default_precision ?? 2;
+				});
+
+			get_dialog_with_currency(test_case.df_options).as("dialog");
+			cy.get_field(fieldname, "Currency").clear();
+			cy.wait(300);
+			cy.fill_field(fieldname, test_case.input, "Currency").blur();
+			cy.get_field(fieldname, "Currency").should("have.value", test_case.blur_expected);
+			cy.hide_dialog();
+		});
+	});
+});

frappe/public/js/frappe/form/controls/currency.js

@@ -7,7 +7,7 @@ frappe.ui.form.ControlCurrency = class ControlCurrency extends frappe.ui.form.Co
 	get_precision() {
 		// always round based on field precision or currency's precision
 		// this method is also called in this.parse()
-		if (!this.df.precision) {
+		if (typeof this.df.precision != "number" && !this.df.precision) {
 			if (frappe.boot.sysdefaults.currency_precision) {
 				this.df.precision = frappe.boot.sysdefaults.currency_precision;
 			} else {

frappe/public/js/frappe/form/formatters.js

@@ -103,9 +103,15 @@ frappe.form.formatters = {
 	},
 	Currency: function (value, docfield, options, doc) {
 		var currency = frappe.meta.get_field_currency(docfield, doc);
-		var precision = cint(
-			docfield.precision ?? frappe.boot.sysdefaults.currency_precision ?? 2
-		);
+
+		let precision;
+		if (typeof docfield.precision == "number") {
+			precision = docfield.precision;
+		} else {
+			precision = cint(
+				docfield.precision || frappe.boot.sysdefaults.currency_precision || 2
+			);
+		}
 
 		// If you change anything below, it's going to hurt a company in UAE, a bit.
 		if (precision > 2) {