From f12afb753afff75d2b06b05c01be7cc76db4b94a Mon Sep 17 00:00:00 2001
From: Sir Robert Burbridge <sirrobert@gmail.com>
Date: Fri, 17 Nov 2023 16:04:42 -0500
Subject: [PATCH] Add better tests and change the way data masking works.

---
 src/interpolate.mjs       | 24 +++++++-------
 test/interpolate.test.mjs | 67 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 77 insertions(+), 14 deletions(-)

diff --git a/src/interpolate.mjs b/src/interpolate.mjs
index f92b190..c2cf968 100644
--- a/src/interpolate.mjs
+++ b/src/interpolate.mjs
@@ -12,17 +12,15 @@ export function interpolate(node, rootData, options = {}) {
 	return node;
 }
 
-function getMaskedData(node, ancestors) {
-	let masked = { ...node.data };
+function getMaskedData(node, ancestors, mask = {}) {
+	var foo = Object.assign(
+		{},
+		...(ancestors.map((ancestor) => (ancestor?.data?.interp || {}))),
+		node?.data?.interp || {},
+		mask
+	);
 
-	for (let i = ancestors.length - 1; i >= 0; i--) {
-		const ancestor = ancestors[i];
-		if (ancestor.data && ancestor.data.interp) {
-			masked.interp = { ...ancestor.data.interp, ...masked.interp };
-		}
-	}
-
-	return masked;
+	return foo;
 }
 
 function interpolateNode(node, ancestors) {
@@ -33,11 +31,11 @@ function interpolateNode(node, ancestors) {
 			if (typeof node.properties[key] === 'string') {
 				node.properties[key] = interpolateString(
 					node.properties[key],
-					data.interp
+					data
 				);
 			} else if (Array.isArray(node.properties[key])) {
 				node.properties[key] = node.properties[key].map(
-					(value) => interpolateString(value, data.interp)
+					(value) => interpolateString(value, data)
 				);
 			}
 			else {
@@ -47,7 +45,7 @@ function interpolateNode(node, ancestors) {
 	}
 
 	if (node.type === 'text' && node.value) {
-		node.value = interpolateString(node.value, data.interp);
+		node.value = interpolateString(node.value, data);
 	}
 
 	return node;
diff --git a/test/interpolate.test.mjs b/test/interpolate.test.mjs
index 12a0f50..ca1590f 100644
--- a/test/interpolate.test.mjs
+++ b/test/interpolate.test.mjs
@@ -56,7 +56,7 @@ describe("interpolate()", () => {
 			const node = { data: { interp: { test: 'value' } } };
 			const ancestors = [{ data: { interp: { parentValue: 'parent' } } }];
 			const maskedData = __testExports.getMaskedData(node, ancestors);
-			expect(maskedData.interp).toEqual({ parentValue: 'parent', test: 'value' });
+			expect(maskedData).toEqual({ parentValue: 'parent', test: 'value' });
 		});
 	});
 
@@ -191,3 +191,68 @@ describe("interpolate()", () => {
 	})
 
 });
+
+describe("getMaskedData()", () => {
+	it("should import", () => {
+		expect(__testExports.getMaskedData).toBeDefined();
+	})
+
+	it("should shadow ancestor data with current node data", () => {
+		const maskedData = __testExports.getMaskedData(
+			{
+				data: { interp: { foo: "child" } },
+			},
+			// Give a list of ancestors.
+			[
+				{ data: { interp: { foo: "root" } } },
+				{ data: { interp: { foo: "parent" } } },
+			],
+		);
+
+		expect(maskedData).toEqual({foo: "child"})
+	});
+
+	it("should shadow ancestor data with current node data", () => {
+		const maskedData = __testExports.getMaskedData(
+			{
+				data: { interp: { foo: "child" } },
+			},
+			// Give a list of ancestors.
+			[
+				{ data: { interp: { foo: "root" } } },
+				{ data: { interp: { foo: "parent" } } },
+			],
+		);
+
+		expect(maskedData).toEqual({foo: "child"})
+	});
+
+	it("should shadow earlier ancestors with later ancestor data", () => {
+		const maskedData = __testExports.getMaskedData(
+			{
+				data: { interp: {} },
+			},
+			// Give a list of ancestors.
+			[
+				{ data: { interp: { foo: "root" } } },
+				{ data: { interp: { foo: "parent" } } },
+			],
+		);
+
+		expect(maskedData).toEqual({foo: "parent"})
+	});
+
+	it("should shadow earlier ancestors without current data", () => {
+		const maskedData = __testExports.getMaskedData(
+			{ data: {} },
+			// Give a list of ancestors.
+			[
+				{ data: { interp: { foo: "root" } } },
+				{ data: { interp: { foo: "parent" } } },
+			],
+		);
+
+		expect(maskedData).toEqual({foo: "parent"})
+	});
+
+});