@babel/helper-validator-identifier

What is @babel/helper-validator-identifier?

The @babel/helper-validator-identifier npm package is a utility library used by Babel to validate string identifiers according to the ECMAScript specification. It provides functions to determine if a string is a valid identifier name, which is useful when manipulating code in a way that needs to adhere to JavaScript naming conventions.

What are @babel/helper-validator-identifier's main functionalities?

isValidIdentifier

Checks if a string is a valid ECMAScript identifier name.

const isValid = require('@babel/helper-validator-identifier').isValidIdentifier;
console.log(isValid('validName')); // true
console.log(isValid('123invalid')); // false

isIdentifierStart

Checks if a character code can start an ECMAScript identifier.

const isIdentifierStart = require('@babel/helper-validator-identifier').isIdentifierStart;
console.log(isIdentifierStart('v'.charCodeAt(0))); // true
console.log(isIdentifierStart('1'.charCodeAt(0))); // false

isIdentifierChar

Checks if a character code can be part of an ECMAScript identifier.

const isIdentifierChar = require('@babel/helper-validator-identifier').isIdentifierChar;
console.log(isIdentifierChar('n'.charCodeAt(0))); // true
console.log(isIdentifierChar('!'.charCodeAt(0))); // false

Other packages similar to @babel/helper-validator-identifier

esutils

esutils is a utility box for ECMAScript language tools. It includes a keyword check similar to @babel/helper-validator-identifier, but also provides other utilities for AST manipulation and code generation.

jstransform

jstransform is a simple utility for pluggable JS syntax transforms using the visitor pattern. It includes utilities for identifier validation, but it is more focused on transforming code rather than just validating identifiers.

jscodeshift

jscodeshift is a toolkit for running codemods over multiple JavaScript or TypeScript files. It includes utilities for working with identifiers within the context of transforming code, but it is more comprehensive and is designed for writing and applying codemods.

README

@babel/helper-validator-identifier

Validate identifier/keywords name

See our website @babel/helper-validator-identifier for more information.

Install

Using npm:

npm install --save @babel/helper-validator-identifier

or using yarn:

yarn add @babel/helper-validator-identifier

Changelog

v7.25.9 (2024-10-22)

:bug: Bug Fix

• babel-parser, babel-template, babel-types
  • #16905 fix: Keep type annotations in syntacticPlaceholders mode (@liuxingbaoyu)
• babel-helper-compilation-targets, babel-preset-env
  • #16907 fix: support BROWSERSLIST{,_CONFIG} env (@JLHwung)
• Other
  • #16884 Analyze ClassAccessorProperty to prevent the no-undef rule (@victorenator)

:house: Internal

• babel-helper-transform-fixture-test-runner
  • #16914 remove test options flaky (@JLHwung)

:running_woman: Performance

• babel-parser, babel-types
  • #16918 perf: Make VISITOR_KEYS etc. faster to access (@liuxingbaoyu)