estraverse 5.3.0: traverse

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify estraverse.traverse in pkg:npm/estraverse@5.3.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/estraverse@5.3.0
Demonstrate these symbols/APIs:
  - estraverse.traverse
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:49b5ecf3d6a97f65c7a848ea54a9264e50799cdf42d3170ec46da4e1181cec69","constraints":{"executionContext":"node"},"contract":["estraverse.traverse traverses AST nodes with enter and leave visitors in depth-first order","estraverse.traverse provides node and parent references during traversal","estraverse.traverse skips child node traversal when VisitorOption.Skip is returned","estraverse.traverse terminates AST traversal immediately when VisitorOption.Break is returned","estraverse.traverse provides controller methods this.skip(), this.break(), this.parents(), and this.path()"],"goal":"verify estraverse.traverse in pkg:npm/estraverse@5.3.0","kind":"HOW","packages":["pkg:npm/estraverse@5.3.0"],"schemaVersion":1,"symbols":["estraverse.traverse"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/estraverse@5.3.0"],"schemaVersion":1,"subject":"pkg:npm/estraverse@5.3.0","symbols":["estraverse.traverse"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-estraverse",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-estraverse",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "estraverse": "5.3.0"
      }
    },
    "node_modules/estraverse": {
      "version": "5.3.0",
      "resolved": "https://registry.npmjs.org/estraverse/-/estraverse-5.3.0.tgz",
      "integrity": "sha512-MMdARuVEQziNTeJD8DgMqmhwR11BRQ/cBP+pLtYdSTnf3MIO8fFeiINEbX36ZdNlfU/7A9f3gUw49B3oQsvwBA==",
      "license": "BSD-2-Clause",
      "engines": {
        "node": ">=4.0"
      }
    }
  }
}

{
  "name": "sample-estraverse",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "estraverse": "5.3.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify estraverse.traverse in pkg:npm/estraverse@5.3.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/estraverse@5.3.0"
  ],
  "symbols": [
    "estraverse.traverse"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

import estraverse from "estraverse";

export function collectIdentifiers(ast) {
  const identifiers = [];
  estraverse.traverse(ast, {
    enter(node) {
      if (node.type === "Identifier") {
        identifiers.push(node.name);
      }
    }
  });
  return identifiers;
}

export function recordTraversalOrder(ast) {
  const events = [];
  estraverse.traverse(ast, {
    enter(node, parent) {
      events.push(`enter:${node.type}:${parent ? parent.type : "root"}`);
    },
    leave(node, parent) {
      events.push(`leave:${node.type}:${parent ? parent.type : "root"}`);
    }
  });
  return events;
}

export function findFirstIdentifier(ast, targetName) {
  let found = null;
  estraverse.traverse(ast, {
    enter(node) {
      if (node.type === "Identifier" && node.name === targetName) {
        found = node;
        return estraverse.VisitorOption.Break;
      }
    }
  });
  return found;
}

export function collectTopLevelIdentifiers(ast) {
  const identifiers = [];
  estraverse.traverse(ast, {
    enter(node, parent) {
      if (node.type === "FunctionDeclaration" || node.type === "BlockStatement") {
        return estraverse.VisitorOption.Skip;
      }
      if (node.type === "Identifier") {
        identifiers.push(node.name);
      }
    }
  });
  return identifiers;
}

export function inspectIdentifierContext(ast, targetName) {
  let context = null;
  estraverse.traverse(ast, {
    enter(node) {
      if (node.type === "Identifier" && node.name === targetName) {
        context = {
          node,
          parents: this.parents().map(p => p.type),
          path: [...this.path()]
        };
        this.break();
      }
    }
  });
  return context;
}

export function skipSubtreeUsingController(ast, skipType) {
  const visited = [];
  estraverse.traverse(ast, {
    enter(node) {
      visited.push(node.type);
      if (node.type === skipType) {
        this.skip();
      }
    }
  });
  return visited;
}

import assert from "node:assert/strict";
import estraverse from "estraverse";
import {
  collectIdentifiers,
  recordTraversalOrder,
  findFirstIdentifier,
  collectTopLevelIdentifiers,
  inspectIdentifierContext,
  skipSubtreeUsingController
} from "../src/index.mjs";

// Contract 1: estraverse.traverse traverses AST nodes with enter and leave visitors in depth-first order
{
  const ast = {
    type: "Program",
    body: [
      {
        type: "ExpressionStatement",
        expression: {
          type: "BinaryExpression",
          operator: "+",
          left: { type: "Identifier", name: "a" },
          right: { type: "Literal", value: 1 }
        }
      }
    ]
  };

  const order = recordTraversalOrder(ast);
  assert.deepEqual(order, [
    "enter:Program:root",
    "enter:ExpressionStatement:Program",
    "enter:BinaryExpression:ExpressionStatement",
    "enter:Identifier:BinaryExpression",
    "leave:Identifier:BinaryExpression",
    "enter:Literal:BinaryExpression",
    "leave:Literal:BinaryExpression",
    "leave:BinaryExpression:ExpressionStatement",
    "leave:ExpressionStatement:Program",
    "leave:Program:root"
  ]);

  const identifiers = collectIdentifiers(ast);
  assert.deepEqual(identifiers, ["a"]);
}

// Contract 2: estraverse.traverse provides node and parent references during traversal
{
  const ast = {
    type: "Program",
    body: [
      {
        type: "VariableDeclaration",
        kind: "let",
        declarations: [
          {
            type: "VariableDeclarator",
            id: { type: "Identifier", name: "count" },
            init: { type: "Literal", value: 0 }
          }
        ]
      }
    ]
  };

  const pairs = [];
  estraverse.traverse(ast, {
    enter(node, parent) {
      pairs.push({
        childType: node.type,
        parentType: parent ? parent.type : null
      });
    }
  });

  assert.equal(pairs.length, 5);
  assert.deepEqual(pairs[0], { childType: "Program", parentType: null });
  assert.deepEqual(pairs[1], { childType: "VariableDeclaration", parentType: "Program" });
  assert.deepEqual(pairs[2], { childType: "VariableDeclarator", parentType: "VariableDeclaration" });
  assert.deepEqual(pairs[3], { childType: "Identifier", parentType: "VariableDeclarator" });
  assert.deepEqual(pairs[4], { childType: "Literal", parentType: "VariableDeclarator" });
}

// Contract 3: estraverse.traverse skips child node traversal when VisitorOption.Skip is returned
{
  const ast = {
    type: "Program",
    body: [
      {
        type: "VariableDeclaration",
        kind: "const",
        declarations: [
          {
            type: "VariableDeclarator",
            id: { type: "Identifier", name: "topLevel" },
            init: { type: "Literal", value: "visible" }
          }
        ]
      },
      {
        type: "FunctionDeclaration",
        id: { type: "Identifier", name: "fn" },
        params: [],
        body: {
          type: "BlockStatement",
          body: [
            {
              type: "VariableDeclaration",
              kind: "let",
              declarations: [
                {
                  type: "VariableDeclarator",
                  id: { type: "Identifier", name: "nestedHidden" },
                  init: { type: "Literal", value: 123 }
                }
              ]
            }
          ]
        }
      },
      {
        type: "ExpressionStatement",
        expression: {
          type: "Identifier",
          name: "afterFunction"
        }
      }
    ]
  };

  const topIdentifiers = collectTopLevelIdentifiers(ast);
  assert.deepEqual(topIdentifiers, ["topLevel", "afterFunction"]);
}

// Contract 4: estraverse.traverse terminates AST traversal immediately when VisitorOption.Break is returned
{
  const ast = {
    type: "Program",
    body: [
      {
        type: "ExpressionStatement",
        expression: { type: "Identifier", name: "first" }
      },
      {
        type: "ExpressionStatement",
        expression: { type: "Identifier", name: "target" }
      },
      {
        type: "ExpressionStatement",
        expression: { type: "Identifier", name: "unreached" }
      }
    ]
  };

  const visitedTypes = [];
  const found = findFirstIdentifier(ast, "target");
  assert.ok(found);
  assert.equal(found.name, "target");

  estraverse.traverse(ast, {
    enter(node) {
      visitedTypes.push(node.type);
      if (node.type === "Identifier" && node.name === "target") {
        return estraverse.VisitorOption.Break;
      }
    }
  });

  assert.deepEqual(visitedTypes, [
    "Program",
    "ExpressionStatement",
    "Identifier",
    "ExpressionStatement",
    "Identifier"
  ]);
}

// Contract 5: estraverse.traverse provides controller methods this.skip(), this.break(), this.parents(), and this.path()
{
  const ast = {
    type: "Program",
    body: [
      {
        type: "VariableDeclaration",
        kind: "const",
        declarations: [
          {
            type: "VariableDeclarator",
            id: { type: "Identifier", name: "x" },
            init: { type: "Literal", value: 1 }
          }
        ]
      },
      {
        type: "ExpressionStatement",
        expression: {
          type: "Identifier",
          name: "targetContext"
        }
      }
    ]
  };

  const context = inspectIdentifierContext(ast, "targetContext");
  assert.ok(context);
  assert.equal(context.node.name, "targetContext");
  assert.deepEqual(context.parents, ["Program", "ExpressionStatement"]);
  assert.deepEqual(context.path, ["body", 1, "expression"]);

  const visited = skipSubtreeUsingController(ast, "VariableDeclaration");
  assert.deepEqual(visited, [
    "Program",
    "VariableDeclaration",
    "ExpressionStatement",
    "Identifier"
  ]);
}

console.log("All estraverse.traverse contract assertions passed.");