Method isPure

lib/javascript/JavascriptParser.js:5090–5334

* Checks whether this javascript parser is pure. * @param {Expression | Declaration | PrivateIdentifier | MaybeNamedFunctionDeclaration | MaybeNamedClassDeclaration | null | undefined} expr an expression * @param {number} commentsStartPos source position from which annotation comments are checke

(expr, commentsStartPos)

	 * @returns {boolean} true, when the expression is pure
	 */
	isPure(expr, commentsStartPos) {
		if (!expr) return true;
		const result = this.hooks.isPure
			.for(expr.type)
			.call(expr, commentsStartPos);
		if (typeof result === "boolean") return result;
		switch (expr.type) {
			case "ClassDeclaration":
			case "ClassExpression": {
				if (expr.body.type !== "ClassBody") return false;
				if (
					expr.superClass &&
					!this.isPure(expr.superClass, /** @type {Range} */ (expr.range)[0])
				) {
					return false;
				}
				const items = expr.body.body;
				return items.every((item) => {
					if (item.type === "StaticBlock") {
						return false;
					}

					if (
						item.computed &&
						item.key &&
						!this.isPure(
							item.key,
							/** @type {Range} */
							(item.range)[0]
						)
					) {
						return false;
					}

					if (
						item.static &&
						item.value &&
						!this.isPure(
							item.value,
							item.key
								? /** @type {Range} */ (item.key.range)[1]
								: /** @type {Range} */ (item.range)[0]
						)
					) {
						return false;
					}

					if (
						expr.superClass &&
						item.type === "MethodDefinition" &&
						item.kind === "constructor"
					) {
						return false;
					}

					return true;
				});
			}