meval

meval - m(imic) eval

Info

• This is not a "safe JavaScript eval"!
• This library only mimics eval() functionality to some point.
• It always returns the value of given expression. You always need to provide context in which it will be executed (context must be an Object).
• Pure JavaScript! No dependencies! ^^,
• Minified version is only ~16KB

What's working

• one-argument operators:
  • ! ...
  • ~ ...
  • + ...
  • - ...
  • typeof ...
• two-argument operators:
  • ... . ... (member accessor)
  • ... * ...
  • ... / ...
  • ... % ...
  • ... + ...
  • ... - ...
  • ... >= ...
  • ... <= ...
  • ... > ...
  • ... < ...
  • ... instanceof ...
  • ... in ...
  • ... === ...
  • ... !== ...
  • ... == ...
  • ... != ...
  • ... && ...
  • ... || ...
• three-argument operator:
  • ... ? ... : ...
• Strings, Numbers (both Integers and Floats) and Booleans
  • Node: Interpolation in Strings is not planned for now to be implemented
• properties:
  • undefined
  • null
  • NaN
  • Infinity
• grouping (paranthesis)
• calling methods
  • support nested methods (e.g. foo(1, bar(item.a, item.b)))
• accessing allowed global Object:
  • Date
  • Math
  • Number
  • String
  • Array
  • Object
• mixing above

TODO

• one-argument operators:
  • new (I don't know if it's good idea?)

Usage

Install

It's UMD package, so you can use it both: client-side (browser) and server-side (node.js). Probably you want to just intall it with npm:

npm install --save meval

And then just require it:

const meval = require('meval');

But if you don't want to use npm, you can always simply download eg. minified version right from Releases.

Run

/**
 * @param {String} expression Expression to be parsed
 * @param {Object} context Context for expression
 */
meval(expression, context)

Example

<< meval('item.a + item.b * 5', { item: { a: 2, b: 3 } })
>> 17

Authors

• Marek Sierociński - marverix

See also the list of contributors who participated in this project.

License

This project is licensed under the ISC License - see the LICENSE file for details.