Registry / serialization / estree-util-visit

estree-util-visit

library2.0.0jsnpmunverified

estree-util-visit is a core utility within the unified (syntax-tree) ecosystem designed for traversing ESTree (and esast) abstract syntax trees. It enables developers to visit nodes in a depth-first traversal (preorder and/or postorder) for analysis or transformation. The current stable version is 2.0.0. The package distinguishes itself by duck-typing fields for node identification, eliminating the need for a predefined dictionary of node fields, which can simplify usage compared to other walkers. It provides symbolic controls (CONTINUE, EXIT, SKIP) for fine-grained traversal management. Releases are generally tied to ecosystem-wide updates or targeted feature enhancements. Since v2, it is an ESM-only package and requires Node.js 16 or newer.

serialization

npm install estree-util-visit

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · ESTREE-UTIL-VISIT

estree-util-visit

serializationjavascriptv2.0.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

visit

✓ import { visit } from 'estree-util-visit'

✗ const visit = require('estree-util-visit').visit

Package is ESM-only since v2.0.0, so CommonJS `require` is not supported. There is no default export.

CONTINUE

✓ import { CONTINUE } from 'estree-util-visit'

✗ import CONTINUE from 'estree-util-visit'

Control symbols like CONTINUE, EXIT, and SKIP are named exports, not default. ESM-only.

Visitor

✓ import type { Visitor } from 'estree-util-visit'

TypeScript types are shipped with the package. Import types using `import type`.

Demonstrates parsing an ESTree with Acorn and then traversing it with `estree-util-visit` to find and log literal values, showcasing traversal control with `EXIT`.

import { parse } from 'acorn' import { visit, CONTINUE, EXIT, SKIP } from 'estree-util-visit' const tree = parse( 'export function example() { const x = 1 + "2"; console.log(x); if (process.env.DEBUG === "true") { process.exit(3) } }', { sourceType: 'module', ecmaVersion: 2020 } ) let literalsFound = 0; visit(tree, function (node) { if (node.type === 'Literal' && 'value' in node) { console.log(`Found literal: ${JSON.stringify(node.value)}`); literalsFound++; } if (literalsFound >= 2) { console.log('Enough literals found, exiting traversal.'); return EXIT; } return CONTINUE; }) // Example of using enter/leave visitors visit(tree, { enter(node) { // console.log(`Entering: ${node.type}`); }, leave(node) { // console.log(`Leaving: ${node.type}`); } });

Debug

Known issues

breakingVersion 2.0.0 of `estree-util-visit` now requires Node.js 16 or higher.

fix

Ensure your Node.js environment is version 16 or newer. Update your `package.json` engines field or CI/CD pipelines accordingly.

affects: >=2.0.0

breaking`estree-util-visit` is now an ESM-only package and utilizes the `exports` field in `package.json`. CommonJS `require()` is no longer supported.

fix

Refactor your codebase to use ES module `import` statements (e.g., `import { visit } from 'estree-util-visit'`). Adjust build configurations (e.g., Webpack, Rollup) or Jest setups to handle ESM correctly.

affects: >=2.0.0

breakingThe `visit` function's callback arguments now pass `undefined` instead of `null` for certain optional values (e.g., `field`, `index`).

fix

Update your visitor functions to expect and handle `undefined` instead of `null` for these arguments, e.g., `if (field !== undefined)`.

affects: >=2.0.0

gotchaThe package updated its `@types/unist` dependency. If your project also directly depends on `@types/unist`, you might encounter type conflicts or unexpected type behavior if your versions are incompatible.

fix

Ensure that your project's `@types/unist` dependency (if any) is updated to a compatible version, or remove it if it's implicitly handled by `estree-util-visit`.

affects: >=2.0.0

Errors

Common errors & fixes

Error [ERR_REQUIRE_ESM]: require() of ES Module /path/to/node_modules/estree-util-visit/index.js from /your/file.js not supported.

Attempting to use `require()` to import `estree-util-visit`, which is an ESM-only package since version 2.0.0.

fix

Change your import statement from `const { visit } = require('estree-util-visit')` to `import { visit } from 'estree-util-visit'`. Ensure your project is configured for ESM.

TypeError: (0, _estree_util_visit.visit) is not a function

This error typically occurs when trying to import `visit` as a default export or using an incorrect named import syntax in an ESM environment, or when transpilers misinterpret the import.

fix

Verify that you are using `import { visit } from 'estree-util-visit'` and not `import visit from 'estree-util-visit'` (there is no default export). Check your Babel/TypeScript configuration if transpiling.

ReferenceError: CONTINUE is not defined

The control symbols (CONTINUE, EXIT, SKIP) are named exports and must be explicitly imported.

fix

Add `CONTINUE` (and any other control symbols you use) to your named import: `import { visit, CONTINUE } from 'estree-util-visit'`.

Upgrade

Version history

2.0.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/syntax-tree/estree-util-visit ↗

packagehttps://www.npmjs.com/package/estree-util-visit ↗

homepagehttps://unifiedjs.com ↗