move error to compiler_errors

src/compiler/compile/compiler_errors.ts

@@ -40,6 +40,10 @@ export default {
 		code: 'invalid-binding',
 		message: 'Cannot bind to a variable declared with {#await ... then} or {:catch} blocks'
 	},
+	invalid_binding_const: {
+		code: 'invalid-binding',
+		message: 'Cannot bind to a variable declared with {@const ...}'
+	},
 	invalid_binding_writibale: {
 		code: 'invalid-binding',
 		message: 'Cannot bind to a variable which is not writable'
@@ -241,5 +245,21 @@ export default {
 	invalid_directive_value: {
 		code: 'invalid-directive-value',
 		message: 'Can only bind to an identifier (e.g. `foo`) or a member expression (e.g. `foo.bar` or `foo[baz]`)'
-	}
+	},
+	invalid_const_placement: {
+		code: 'invalid-const-placement',
+		message: '{@const} must be the immediate child of {#each}, {:then}, {:catch}, <svelte:fragment> and <Component>'
+	},
+	invalid_const_declaration: (name: string) => ({
+		code: 'invalid-const-declaration',
+		message: `'${name}' has already been declared`
+	}),
+	invalid_const_update: (name: string) => ({
+		code: 'invalid-const-update',
+		message: `'${name}' is declared using {@const ...} and it is read-only`
+	}),
+	cyclical_constant_tags: (cycle: string[]) => ({
+		code: 'cyclical-constant-tags',
+		message: `Cyclical dependency detected: ${cycle.join(' → ')}`
+	})
 };

src/compiler/compile/nodes/Binding.ts

@@ -58,10 +58,7 @@ export default class Binding extends Node {
 				return;
 			}
 			if (scope.is_const(name)) {
-				component.error(this, {
+				component.error(this, compiler_errors.invalid_binding_const);
-					code: 'invalid-binding',
-					message: 'Cannot bind to a variable declared with {@const ...}'
-				});
 			}
 
 			scope.dependencies_for_name.get(name).forEach(name => {

src/compiler/compile/nodes/ConstTag.ts

@@ -9,6 +9,7 @@ import { walk } from 'estree-walker';
 import { extract_identifiers } from 'periscopic';
 import is_reference from 'is-reference';
 import get_object from '../utils/get_object';
+import compiler_errors from '../compiler_errors';
 
 const allowed_parents = new Set(['EachBlock', 'CatchBlock', 'ThenBlock', 'InlineComponent', 'SlotTemplate']);
 
@@ -26,7 +27,7 @@ export default class ConstTag extends Node {
 		super(component, parent, scope, info);
 
 		if (!allowed_parents.has(parent.type)) {
-			component.error(info, { code: 'invalid-const-placement', message: '{@const} must be the immediate child of {#each}, {:then}, {:catch}, <svelte:fragment> and <Component>' });
+			component.error(info, compiler_errors.invalid_const_placement);
 		}
 		this.node = info;
 		this.scope = scope;
@@ -37,7 +38,7 @@ export default class ConstTag extends Node {
       assignees.add(name);
 			const owner = this.scope.get_owner(name);
 			if (owner === parent) {
-				component.error(info, { code: 'invalid-const-declaration', message: `'${name}' has already been declared` });
+				component.error(info, compiler_errors.invalid_const_declaration(name));
 			}
     });
 
@@ -51,14 +52,14 @@ export default class ConstTag extends Node {
       }
     });
 	}
-	
+
 	parse_expression() {
 		unpack_destructuring(this.contexts, this.node.expression.left);
 		this.expression = new Expression(this.component, this, this.scope, this.node.expression.right);
 		this.contexts.forEach(context => {
 			const owner = this.scope.get_owner(context.key.name);
 			if (owner && owner.type === 'ConstTag' && owner.parent === this.parent) {
-				this.component.error(this.node, { code: 'invalid-const-declaration', message: `'${context.key.name}' has already been declared` });
+				this.component.error(this.node, compiler_errors.invalid_const_declaration(context.key.name));
 			}
 			this.scope.add(context.key.name, this.expression.dependencies, this);
 		});

src/compiler/compile/nodes/shared/Expression.ts

@@ -134,10 +134,7 @@ export default class Expression {
 					names.forEach(name => {
 						if (template_scope.names.has(name)) {
 							if (template_scope.is_const(name)) {
-								component.error(node, {
+								component.error(node, compiler_errors.invalid_const_update(name));
-									code: 'invalid-const-update',
-									message: `'${name}' is declared using {@const ...} and it is read-only`
-								});
 							}
 
 							template_scope.dependencies_for_name.get(name).forEach(name => {

src/compiler/compile/nodes/shared/get_const_tags.ts

@@ -4,6 +4,7 @@ import ConstTag from '../ConstTag';
 import map_children from './map_children';
 import { INodeAllowConstTag, INode } from '../interfaces';
 import check_graph_for_cycles from '../../utils/check_graph_for_cycles';
+import compiler_errors from '../../compiler_errors';
 
 export default function get_const_tags(children: TemplateNode[], component: Component, node: INodeAllowConstTag, parent: INode): [ConstTag[], Array<Exclude<INode, ConstTag>>] {
   const const_tags: ConstTagType[] = [];
@@ -67,10 +68,7 @@ function sort_consts_nodes(consts_nodes: ConstTag[], component: Component) {
   if (cycle && cycle.length) {
     const nodeList = lookup.get(cycle[0]);
     const node = nodeList[0];
-    component.error(node.node, {
+    component.error(node.node, compiler_errors.cyclical_constant_tags(cycle));
-      code: 'cyclical-constant-tags',
-      message: `Cyclical dependency detected: ${cycle.join(' → ')}`
-    });
   }
 
   const add_node = (node: ConstNode) => {