is-expression

is-expression

Validates a string as a JavaScript expression

Installation

npm install is-expression

Usage

isExpression(src[, options])

Validates a string as a JavaScript expression.

src contains the source.

options can contain any Acorn options (since we use Acorn under-the-hood), or any of the following:

• throw: Throw an error if the string is not an expression. The error can be an Acorn error, with location information in err.loc and err.pos. Defaults to false.
• strict: Use strict mode when trying to parse the string. Defaults to false. Even if this option is false, if you have provided options.sourceType === 'module' which imples strict mode under ES2015, strict mode will be used.
• lineComment: When true, allows line comments in the expression. Defaults to false for safety.

See the examples below for usage.

Examples

var isExpression = require('is-expression')

isExpression('myVar')
//=> true
isExpression('var')
//=> false
isExpression('["an", "array", "\'s"].indexOf("index")')
//=> true

isExpression('var', {throw: true})
// SyntaxError: Unexpected token (1:0)
//     at Parser.pp.raise (acorn/dist/acorn.js:940:13)
//     at ...

isExpression('public')
//=> true
isExpression('public', {strict: true})
//=> false

isExpression('abc // my comment')
//=> false
isExpression('abc // my comment', {lineComment: true})
//=> true

License

MIT

Similar packages

Other packages similar to is-expression

acorn

Acorn is a small, fast, JavaScript-based JavaScript parser. It can be used to parse JavaScript code into an abstract syntax tree (AST), which can then be analyzed or transformed. Compared to is-expression, Acorn provides more comprehensive parsing capabilities, including support for full JavaScript syntax, but it is more complex to use for simple expression validation.

esprima

Esprima is a high-performance, standard-compliant ECMAScript parser written in JavaScript. It parses JavaScript programs and returns an abstract syntax tree (AST). Like Acorn, Esprima offers more extensive parsing features than is-expression, making it suitable for more complex code analysis tasks beyond simple expression validation.