1 files changed, 69 insertions, 0 deletions
diff --git a/node_modules/@11ty/eleventy/src/Util/ReservedData.js b/node_modules/@11ty/eleventy/src/Util/ReservedData.js
new file mode 100644
index 0000000..d726c73
--- /dev/null
+++ b/node_modules/@11ty/eleventy/src/Util/ReservedData.js
@@ -0,0 +1,69 @@
+class EleventyReservedDataError extends TypeError {}
+
+class ReservedData {
+	static properties = [
+		// "pkg", // Object.freeze’d upstream
+		// "eleventy", // Object.freeze’d upstream
+		// "page" is only frozen for specific subproperties below
+		"content",
+		"collections",
+	];
+
+	static pageProperties = [
+		"date",
+		"inputPath",
+		"fileSlug",
+		"filePathStem",
+		"outputFileExtension",
+		"templateSyntax",
+		"url",
+		"outputPath",
+		// not yet `excerpt` or `lang` set via front matter and computed data
+	];
+
+	// Check in the data cascade for reserved data properties.
+	static getReservedKeys(data) {
+		if (!data) {
+			return [];
+		}
+
+		let keys = this.properties.filter((key) => {
+			return key in data;
+		});
+
+		if ("page" in data) {
+			if (typeof data.page === "object") {
+				for (let key of this.pageProperties) {
+					if (key in data.page) {
+						keys.push(`page.${key}`);
+					}
+				}
+			} else {
+				// fail `page` when set to non-object values.
+				keys.push("page");
+			}
+		}
+		return keys;
+	}
+
+	static check(data) {
+		let reserved = ReservedData.getReservedKeys(data);
+		if (reserved.length === 0) {
+			return;
+		}
+
+		let error = new EleventyReservedDataError(
+			`Cannot override reserved Eleventy properties: ${reserved.join(", ")}`,
+		);
+
+		error.reservedNames = reserved;
+
+		throw error;
+	}
+
+	static isReservedDataError(e) {
+		return e instanceof EleventyReservedDataError;
+	}
+}
+
+export default ReservedData;