CodePathAnalyzer Class — react Architecture

Source Code

packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-analyzer.js lines 723–800

class CodePathAnalyzer {
  /**
   * @param {EventGenerator} eventGenerator An event generator to wrap.
   */
  constructor(emitters) {
    this.emitter = {
      emit(event, ...args) {
        emitters[event]?.(...args);
      },
    };
    this.codePath = null;
    this.idGenerator = new IdGenerator('s');
    this.currentNode = null;
    this.onLooped = this.onLooped.bind(this);
  }

  /**
   * Does the process to enter a given AST node.
   * This updates state of analysis and calls `enterNode` of the wrapped.
   * @param {ASTNode} node A node which is entering.
   * @returns {void}
   */
  enterNode(node) {
    this.currentNode = node;

    // Updates the code path due to node's position in its parent node.
    if (node.parent) {
      preprocess(this, node);
    }

    /*
     * Updates the code path.
     * And emits onCodePathStart/onCodePathSegmentStart events.
     */
    processCodePathToEnter(this, node);

    this.currentNode = null;
  }

  /**
   * Does the process to leave a given AST node.
   * This updates state of analysis and calls `leaveNode` of the wrapped.
   * @param {ASTNode} node A node which is leaving.
   * @returns {void}
   */
  leaveNode(node) {
    this.currentNode = node;

    /*
     * Updates the code path.
     * And emits onCodePathStart/onCodePathSegmentStart events.
     */
    processCodePathToExit(this, node);

    // Emits the last onCodePathStart/onCodePathSegmentStart events.
    postprocess(this, node);

    this.currentNode = null;
  }

  /**
   * This is called on a code path looped.
   * Then this raises a looped event.
   * @param {CodePathSegment} fromSegment A segment of prev.
   * @param {CodePathSegment} toSegment A segment of next.
   * @returns {void}
   */
  onLooped(fromSegment, toSegment) {
    if (fromSegment.reachable && toSegment.reachable) {
      this.emitter.emit(
        'onCodePathSegmentLoop',
        fromSegment,
        toSegment,
        this.currentNode,
      );
    }
  }
}