From ee937c25f7e147fef539714b7a14b32cde6f00a7 Mon Sep 17 00:00:00 2001
From: Lea Verou <lea@verou.me>
Date: Mon, 5 Oct 2020 14:30:37 +0300
Subject: [PATCH] [#20] Remove optional chaining operator

(unsupported by BigQuery)
---
 js/20-gradients.js   |  8 ++++--
 runtime/var-tree.js  |  4 +--
 vars/dependencies.js | 66 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+), 6 deletions(-)
 create mode 100644 vars/dependencies.js

diff --git a/js/20-gradients.js b/js/20-gradients.js
index bd1df9b..9457b55 100644
--- a/js/20-gradients.js
+++ b/js/20-gradients.js
@@ -49,10 +49,12 @@ walkDeclarations(ast, ({property, value}) => {
 
 		// Separate color and position(s)
 		stops = stops.map(s => {
-			let color = s.match(/#[a-f0-9]+|(?:rgba?|hsla?|color)\((\(.*?\)|.)+?\)/)?.[0];
+			let match = s.match(/#[a-f0-9]+|(?:rgba?|hsla?|color)\((\(.*?\)|.)+?\)/);
+			let color = match && match[0];
 
 			if (!color) {
-				color = s.match(keywordRegex)?.[0];
+				let match = s.match(keywordRegex);
+				color = match && match[0];
 			}
 
 			let pos = s.replace(color, "").trim().split(/\s+/);
@@ -79,7 +81,7 @@ walkDeclarations(ast, ({property, value}) => {
 				}
 				// Two positions of which the first is 0 or the same as the last one
 				else if (s.pos.length === 2) {
-					if (parseFLoat(s.pos[0]) === 0 || prev.pos.length === 2 && s.pos[0] === prev.pos?.[1] || prev.pos.length === 1 && s.pos[0] === s.pos[0]) {
+					if (parseFLoat(s.pos[0]) === 0 || prev.pos.length === 2 && s.pos[0] === (prev.pos && prev.pos[1]) || prev.pos.length === 1 && s.pos[0] === s.pos[0]) {
 						ret.hard_stops++;
 					}
 				}
diff --git a/runtime/var-tree.js b/runtime/var-tree.js
index 0ae6730..0479289 100644
--- a/runtime/var-tree.js
+++ b/runtime/var-tree.js
@@ -305,8 +305,6 @@ walkElements(computed, node => {
 	}
 })
 
-
-
 return {summary, computed};
 
 };
@@ -340,7 +338,7 @@ function serializeElement(element) {
 
 		return str;
 	}
-	
+
 	return element;
 }
 
diff --git a/vars/dependencies.js b/vars/dependencies.js
new file mode 100644
index 0000000..ed11556
--- /dev/null
+++ b/vars/dependencies.js
@@ -0,0 +1,66 @@
+export default function compute() {
+
+function walkElements(node, callback, parent) {
+	if (Array.isArray(node)) {
+		for (let n of node) {
+			walkElements(n, callback, node);
+		}
+	}
+	else {
+		callback(node, parent);
+
+		if (node.children) {
+			walkElements(node.children, callback, node);
+		}
+	}
+}
+
+let ret = {
+
+};
+
+function countDependencyLength(declarations, property) {
+	let o = declarations[property];
+
+	if (o === undefined) {
+		return 0;
+	}
+
+	if (!o.references || o.references.length === 0) {
+		return 0;
+	}
+
+	let lengths = o.references.map(p => countDependencyLength(declarations, p));
+
+	return 1 + Math.max(...lengths);
+}
+
+walkElements(vars.computed, (node, parent) => {
+	if (node.declarations) {
+		// Make inheritance explicit
+		if (parent && parent.declarations) {
+			for (let property in parent.declarations) {
+				if (!(property in node.declarations)) {
+					node.declarations[property] = Object.assign({inherited: true}, parent.declarations[property]);
+				}
+			}
+		}
+
+		for (let property in node.declarations) {
+
+			let o = node.declarations[property];
+			if (o.computed && o.computed.trim() === "initial" && o.value.trim() !== "initial") {
+				// Cycle or missing ref
+				incrementByKey(ret, "initial");
+			}
+			else if (o.references) {
+				let depth = countDependencyLength(node.declarations, property);
+				incrementByKey(ret, depth);
+			}
+		}
+	}
+});
+
+return ret;
+
+}