feat: static template expression evaluation

.changeset/calm-beds-decide.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+feat: static template expression evaluation

packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/element.js

@@ -8,6 +8,7 @@ import { is_event_attribute } from '../../../../../utils/ast.js';
 import * as b from '../../../../../utils/builders.js';
 import { build_class_directives_object, build_style_directives_object } from '../RegularElement.js';
 import { build_template_chunk, get_expression_id } from './utils.js';
+import { evaluate_static_expression, DYNAMIC } from '../../../shared/static-evaluation.js';
 
 /**
  * @param {Array<AST.Attribute | AST.SpreadAttribute>} attributes
@@ -131,7 +132,10 @@ export function build_attribute_value(value, context, memoize = (value) => value
 		}
 
 		let expression = /** @type {Expression} */ (context.visit(chunk.expression));
-
+		let evaluated = evaluate_static_expression(expression, context.state);
+		if (evaluated !== DYNAMIC) {
+			return { value: b.literal(evaluated), has_state: false };
+		}
 		return {
 			value: memoize(expression, chunk.metadata.expression),
 			has_state: chunk.metadata.expression.has_state

packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js

@@ -9,6 +9,7 @@ import { regex_is_valid_identifier } from '../../../../patterns.js';
 import is_reference from 'is-reference';
 import { locator } from '../../../../../state.js';
 import { create_derived } from '../../utils.js';
+import { evaluate_static_expression, DYNAMIC } from '../../../shared/static-evaluation.js';
 
 /**
  * @param {ComponentClientTransformState} state
@@ -64,6 +65,13 @@ export function build_template_chunk(
 			node.expression.name !== 'undefined' ||
 			state.scope.get('undefined')
 		) {
+			let evaluated = evaluate_static_expression(node.expression, state);
+			if (evaluated !== DYNAMIC) {
+				if (evaluated != null) {
+					quasi.value.cooked += evaluated + '';
+				}
+				continue;
+			}
 			let value = memoize(
 				/** @type {Expression} */ (visit(node.expression, state)),
 				node.metadata.expression

packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js

@@ -11,6 +11,7 @@ import {
 import * as b from '../../../../../utils/builders.js';
 import { sanitize_template_string } from '../../../../../utils/sanitize_template_string.js';
 import { regex_whitespaces_strict } from '../../../../patterns.js';
+import { evaluate_static_expression, DYNAMIC } from '../../../shared/static-evaluation.js';
 
 /** Opens an if/each block, so that we can remove nodes in the case of a mismatch */
 export const block_open = b.literal(BLOCK_OPEN);
@@ -49,7 +50,15 @@ export function process_children(nodes, { visit, state }) {
 					quasi.value.cooked += escape_html(node.expression.value + '');
 				}
 			} else {
-				expressions.push(b.call('$.escape', /** @type {Expression} */ (visit(node.expression))));
+				let evaluated = evaluate_static_expression(node.expression, state, true);
+				if (evaluated === DYNAMIC) {
+					expressions.push(b.call('$.escape', /** @type {Expression} */ (visit(node.expression))));
+				} else {
+					if (evaluated != null) {
+						quasi.value.cooked += escape_html(evaluated + '');
+					}
+					continue;
+				}
 
 				quasi = b.quasi('', i + 1 === sequence.length);
 				quasis.push(quasi);