esutils
Advanced tools
Package description
The esutils npm package is a utility library for ECMAScript language tools. It provides various utility functions to help with the manipulation and validation of ECMAScript (JavaScript) code.
AST (Abstract Syntax Tree) Validation
This feature allows you to validate if a string is a valid ECMAScript identifier, keyword, or reserved word.
const esutils = require('esutils');
let isValidIdentifier = esutils.keyword.isIdentifierName('myIdentifier'); // trueCode Generation
This feature helps in determining if a string is a reserved word in ECMAScript for a given version.
const esutils = require('esutils');
let isReservedWord = esutils.keyword.isReservedWord('super', 6); // trueLiteral Analysis
This feature provides functions to analyze literals in the AST, such as checking if a node is a string literal.
const esutils = require('esutils');
let isStringLiteral = esutils.ast.isStringLiteral({ type: 'Literal', value: 'Hello' }); // trueAcorn is a small, fast, JavaScript-based JavaScript parser. It provides a similar AST-related utility but with a focus on parsing JavaScript code into an AST.
Estraverse is a library for traversing and updating the AST. It is similar to esutils in that it deals with ASTs but focuses more on traversal and modification rather than validation.
JSHint is a tool that helps to detect errors and potential problems in JavaScript code. While it is not a utility library like esutils, it performs validation of JavaScript code, which is one of the functionalities provided by esutils.
Readme
esutils (esutils) is utility box for ECMAScript language tools.
Return true if provided code is decimal digit.
Return true if provided code is hexadecimal digit.
Return true if provided code is octal digit.
Return true if provided code is white space. White space characters are formally defined in ECMA262.
Return true if provided code is line terminator. Line terminator characters are formally defined in ECMA262.
Return true if provided code can be the first character of ECMA262 Identifier. They are formally defined in ECMA262.
Return true if provided code can be the trailing character of ECMA262 Identifier. They are formally defined in ECMA262.
Return true if provided identifier string is one of Keywords in ECMA262 5.1. They are formally defined in ECMA262. If strict flag is true, this function additionally checks whether id is keyword under strict mode.
Return true if provided identifier string is one of Keywords in ECMA262 6. They are formally defined in ECMA262. If strict flag is true, this function additionally checks whether id is keyword under strict mode.
Return true if provided identifier string is one of restricted words under strict mode: "eval" or "arguments". They are formally defined in ECMA262.
Return true if provided identifier string can be IdentifierName. They are formally defined in ECMA262.
Copyright (C) 2013 Yusuke Suzuki (twitter: @Constellation) and other contributors.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
FAQs
utility box for ECMAScript language tools
The npm package esutils receives a total of 30,594,485 weekly downloads. As such, esutils popularity was classified as popular.
We found that esutils demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 2 open source maintainers collaborating on the project.
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