Method use

lib/util/SourceProcessor.js:70–89

* Register a Babel-style visitor map; calls accumulate per node type. * A bucket is a function (= `{ enter }`) or `{ enter?, exit? }`. * @param {VisitorMap<TNode>} map visitor map keyed by node type * @returns {SourceProcessor<TNode, TProcessOptions>} `this`, for chaining

(map)

	 * @returns {SourceProcessor<TNode, TProcessOptions>} `this`, for chaining
	 */
	use(map) {
		// `map`'s keys are node-type enum members; `Object.keys` stringifies them,
		// so index the compiled array by the number to match the numeric `node.type`.
		for (const type of Object.keys(map)) {
			const key = Number(type);
			const v = map[key];
			let bucket = this._visitors[key];
			if (!bucket) {
				bucket = { enter: [], exit: [] };
				this._visitors[key] = bucket;
			}
			if (typeof v === "function") {
				bucket.enter.push(v);
			} else {
				if (v.enter) bucket.enter.push(v.enter);
				if (v.exit) bucket.exit.push(v.exit);
			}
		}
		return this;
	}

	/**
	 * Run the grammar over `input`, firing visitors in source order. No