is-expression-babylon

is-expression-babylon

Validates a string as a JavaScript expression using Babylon

An alternative version of this module using Acorn instead of Babylon is available at is-expression. While this module aims to support all ECMAScript features, even spec proposals in Stage 0, is-expression is more conservative on the features it implements. Pick your poison.

Installation

npm install is-expression-babylon

Usage

const isExpression = require('is-expression-babylon');

isExpression(src[, options])

Validates a string as a JavaScript expression.

src contains the source.

options can contain any Babylon options, 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.

isExpression.getExpression(src[, options])

Get the Babylon Expression AST node of a string.

src contains the source.

options can contain any Babylon options, or any of the following:

• 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.

If the string is not an expression, an error is thrown.

Examples

const isExpression = require('is-expression-babylon');

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

const expression = isExpression.getExpression('abc');
//=> Node { type: 'Identifier', ... }

License

MIT

Changelog

1.1.0 / 2016-10-11

• Add isExpression.getExpression