From 1e62e0b3b40b8dfabf41692c2d8e90378fff5d44 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 27 Feb 2023 14:12:56 +0100
Subject: [PATCH] simplify

---
 src/compiler/compile/render_ssr/Renderer.ts   |  1 -
 .../utils/collapse_template_literal.ts        | 47 ++++++++-----------
 2 files changed, 20 insertions(+), 28 deletions(-)

diff --git a/src/compiler/compile/render_ssr/Renderer.ts b/src/compiler/compile/render_ssr/Renderer.ts
index 0e4724ea0e..99a2ee3d68 100644
--- a/src/compiler/compile/render_ssr/Renderer.ts
+++ b/src/compiler/compile/render_ssr/Renderer.ts
@@ -125,4 +125,3 @@ export default class Renderer {
 		});
 	}
 }
-
diff --git a/src/compiler/compile/utils/collapse_template_literal.ts b/src/compiler/compile/utils/collapse_template_literal.ts
index bace266ce5..7658e50f02 100644
--- a/src/compiler/compile/utils/collapse_template_literal.ts
+++ b/src/compiler/compile/utils/collapse_template_literal.ts
@@ -1,37 +1,30 @@
 import { TemplateLiteral } from 'estree';
 import { escape_template } from './stringify';
 
-// Collapse string literals together
+/**
+ * Collapse string literals together
+ */ 
 export function collapse_template_literal(literal: TemplateLiteral) {
-	if (literal.quasis.length) {
-		// flatMap() to produce an array containing [quasi, expr, quasi, expr, ..., quasi]
-		const zip = literal.quasis.reduce((acc, cur, index) => {
-			const expr = literal.expressions[index];
-			acc.push(cur);
-			if (expr) {
-				acc.push(expr);
-			}
-			return acc;
-		}, []);
+	const collapsed_quasis = [];
+	const collapsed_expressions = [];
 
+	let cur_quasi = literal.quasis[0];
+
+	// An expression always follows a quasi and vice versa, ending with a quasi
+	for (let i = 0; i < literal.quasis.length; i++) {
+		const expr = literal.expressions[i];
+		const next_quasi = literal.quasis[i + 1];
 		// If an expression is a simple string literal, combine it with its preceding
 		// and following quasi
-		let cur_quasi = zip[0];
-		const new_zip = [cur_quasi];
-		for (let i = 1; i < zip.length; i += 2) {
-			const expr = zip[i];
-			const next_quasi = zip[i + 1];
-			if (expr.type === 'Literal' && typeof expr.value === 'string') {
-				cur_quasi.value.raw += escape_template(expr.value) + next_quasi.value.raw;
-			} else {
-				new_zip.push(expr);
-				new_zip.push(next_quasi);
-				cur_quasi = next_quasi;
-			}
+		if (next_quasi && expr.type === 'Literal' && typeof expr.value === 'string') {
+			cur_quasi.value.raw += escape_template(expr.value) + next_quasi.value.raw;
+		} else {
+			collapsed_expressions.push(expr);
+			collapsed_quasis.push(next_quasi);
+			cur_quasi = next_quasi;
 		}
-
-		// Reconstitute the quasi and expressions arrays
-		literal.quasis = new_zip.filter((_, index) => index % 2 === 0);
-		literal.expressions = new_zip.filter((_, index) => index % 2 === 1);
 	}
+
+	literal.quasis = collapsed_quasis;
+	literal.expressions = collapsed_expressions;
 }