jintr/dist/nodes/LogicalExpression.js

A tiny JavaScript interpreter written in TypeScript.

import BaseJSNode from './BaseJSNode.js';
export default class LogicalExpression extends BaseJSNode {
    run() {
        const { operator, left, right } = this.node;
        const operation = LogicalExpression.operatorMap[operator];
        if (!operation) {
            console.warn('Unhandled logical operator:', operator);
            return undefined;
        }
        return operation(this.visitor, left, right);
    }
}
LogicalExpression.operatorMap = {
    '&&': (visitor, leftNode, rightNode) => {
        const leftValue = visitor.visitNode(leftNode);
        return leftValue === true ? visitor.visitNode(rightNode) : leftValue;
    },
    '||': (visitor, leftNode, rightNode) => {
        const leftValue = visitor.visitNode(leftNode);
        return leftValue || visitor.visitNode(rightNode);
    },
    '??': (visitor, leftNode, rightNode) => {
        const normalizeUndefined = (value, isIdentifier) => isIdentifier && value === 'undefined' ? undefined : value;
        const leftValue = normalizeUndefined(visitor.visitNode(leftNode), leftNode.type === 'Identifier');
        const rightValue = normalizeUndefined(visitor.visitNode(rightNode), rightNode.type === 'Identifier');
        return leftValue ?? rightValue;
    }
};