private evaluateMemberExpression()

in packages/jinja/src/runtime.ts [1135:1174]

• 37 lines of code
• 12 McCabe index (conditional complexity)

	private evaluateMemberExpression(expr: MemberExpression, environment: Environment): AnyRuntimeValue {
		const object = this.evaluate(expr.object, environment);

		let property;
		if (expr.computed) {
			if (expr.property.type === "SliceExpression") {
				return this.evaluateSliceExpression(object, expr.property as SliceExpression, environment);
			} else {
				property = this.evaluate(expr.property, environment);
			}
		} else {
			property = new StringValue((expr.property as Identifier).value);
		}

		let value;
		if (object instanceof ObjectValue) {
			if (!(property instanceof StringValue)) {
				throw new Error(`Cannot access property with non-string: got ${property.type}`);
			}
			value = object.value.get(property.value) ?? object.builtins.get(property.value);
		} else if (object instanceof ArrayValue || object instanceof StringValue) {
			if (property instanceof IntegerValue) {
				value = object.value.at(property.value);
				if (object instanceof StringValue) {
					value = new StringValue(object.value.at(property.value));
				}
			} else if (property instanceof StringValue) {
				value = object.builtins.get(property.value);
			} else {
				throw new Error(`Cannot access property with non-string/non-number: got ${property.type}`);
			}
		} else {
			if (!(property instanceof StringValue)) {
				throw new Error(`Cannot access property with non-string: got ${property.type}`);
			}
			value = object.builtins.get(property.value);
		}

		return value instanceof RuntimeValue ? value : new UndefinedValue();
	}