Initialise variables that are not initialised during construction

src/ast/nodes/ClassBody.ts

@@ -20,12 +20,18 @@ export default class ClassBody extends NodeBase {
 			return true;
 		}
 		return (
-			this.classConstructor &&
+			this.classConstructor !== null &&
 			this.classConstructor.hasEffectsWhenCalledAtPath([], callOptions, options)
 		);
 	}
 
 	initialise() {
-		this.classConstructor = this.body.find(method => method.kind === 'constructor');
+		for (const method of this.body) {
+			if (method.kind === 'constructor') {
+				this.classConstructor = method;
+				return;
+			}
+		}
+		this.classConstructor = null;
 	}
 }

src/ast/nodes/ConditionalExpression.ts

@@ -15,6 +15,7 @@ export default class ConditionalExpression extends NodeBase {
 	alternate: ExpressionNode;
 	consequent: ExpressionNode;
 
+	// Not initialised during construction
 	private hasUnknownTestValue = false;
 
 	forEachReturnExpressionWhenCalledAtPath(

src/ast/nodes/IfStatement.ts

@@ -11,6 +11,7 @@ export default class IfStatement extends StatementBase {
 	consequent: StatementNode;
 	alternate: StatementNode | null;
 
+	// Not initialised during construction
 	private hasUnknownTestValue = false;
 
 	hasEffects(options: ExecutionPathOptions): boolean {

src/ast/nodes/Import.ts

@@ -8,6 +8,7 @@ export default class Import extends NodeBase {
 	type: NodeType.Import;
 	parent: CallExpression;
 
+	// Not initialised during construction
 	private resolutionNamespace: string = undefined;
 	private resolutionInterop: boolean = false;
 	private rendered: boolean = false;

src/ast/nodes/Literal.ts

@@ -57,10 +57,7 @@ export default class Literal<T = LiteralValueTypes> extends NodeBase {
 
 	render(code: MagicString, _options: RenderOptions) {
 		if (typeof this.value === 'string') {
-			(<[number, number][]>code.indentExclusionRanges).push(<[number, number]>[
-				this.start + 1,
-				this.end - 1
-			]);
+			(<[number, number][]>code.indentExclusionRanges).push([this.start + 1, this.end - 1]);
 		}
 	}
 

src/ast/nodes/LogicalExpression.ts

@@ -21,6 +21,7 @@ export default class LogicalExpression extends NodeBase {
 	left: ExpressionNode;
 	right: ExpressionNode;
 
+	// Not initialised during construction
 	private hasUnknownLeftValue = false;
 
 	forEachReturnExpressionWhenCalledAtPath(

src/ast/nodes/ThisExpression.ts

@@ -9,8 +9,10 @@ import { ObjectPath } from '../values';
 export default class ThisExpression extends NodeBase {
 	type: NodeType.ThisExpression;
 
-	variable: ThisVariable;
-	alias: string;
+	private alias: string | null;
+
+	// Not initialised during construction
+	variable: ThisVariable = null;
 
 	bind() {
 		super.bind();
@@ -26,25 +28,21 @@ export default class ThisExpression extends NodeBase {
 	}
 
 	initialise() {
-		const lexicalBoundary = this.scope.findLexicalBoundary();
-
-		if (lexicalBoundary.isModuleScope) {
-			this.alias = this.module.context;
-			if (this.alias === 'undefined') {
-				this.module.warn(
-					{
-						code: 'THIS_IS_UNDEFINED',
-						message: `The 'this' keyword is equivalent to 'undefined' at the top level of an ES module, and has been rewritten`,
-						url: `https://github.com/rollup/rollup/wiki/Troubleshooting#this-is-undefined`
-					},
-					this.start
-				);
-			}
+		this.alias = this.scope.findLexicalBoundary().isModuleScope ? this.module.context : null;
+		if (this.alias === 'undefined') {
+			this.module.warn(
+				{
+					code: 'THIS_IS_UNDEFINED',
+					message: `The 'this' keyword is equivalent to 'undefined' at the top level of an ES module, and has been rewritten`,
+					url: `https://github.com/rollup/rollup/wiki/Troubleshooting#this-is-undefined`
+				},
+				this.start
+			);
 		}
 	}
 
 	render(code: MagicString, _options: RenderOptions) {
-		if (this.alias) {
+		if (this.alias !== null) {
 			code.overwrite(this.start, this.end, this.alias, {
 				storeName: true,
 				contentOnly: false

src/ast/nodes/shared/Node.ts

@@ -81,13 +81,15 @@ export interface ExpressionNode extends ExpressionEntity, Node {}
 export class NodeBase implements ExpressionNode {
 	type: string;
 	keys: string[];
-	included: boolean = false;
 	scope: Scope;
 	start: number;
 	end: number;
 	module: Module;
 	parent: Node | { type?: string };
 
+	// Not initialised during construction
+	included: boolean = false;
+
 	constructor(
 		esTreeNode: GenericEsTreeNode,
 		// we need to pass down the node constructors to avoid a circular dependency