node-event-generator.js
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/**
* @fileoverview The event generator for AST nodes.
* @author Toru Nagashima
*/
"use strict";
//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------
/**
* The event generator for AST nodes.
* This implements below interface.
*
* ```ts
* interface EventGenerator {
* emitter: EventEmitter;
* enterNode(node: ASTNode): void;
* leaveNode(node: ASTNode): void;
* }
* ```
*/
class NodeEventGenerator {
/**
* @param {EventEmitter} emitter - An event emitter which is the destination of events.
*/
constructor(emitter) {
this.emitter = emitter;
}
/**
* Emits an event of entering AST node.
* @param {ASTNode} node - A node which was entered.
* @returns {void}
*/
enterNode(node) {
this.emitter.emit(node.type, node);
}
/**
* Emits an event of leaving AST node.
* @param {ASTNode} node - A node which was left.
* @returns {void}
*/
leaveNode(node) {
this.emitter.emit(`${node.type}:exit`, node);
}
}
module.exports = NodeEventGenerator;