NOTE
safe-eval 0.3.0 and below are affected by a sandbox breakout vulnerability - NSP 337, CVE-2017-16088.
Version 0.4.0 fixes this vulnerability. It is highly recommended to upgrade to the latest version if you are using safe-eval for executing code not generated by yourself. Thanks @kauegimenes for the patch.
UPDATE 27/08/2018: There are still ways to crash the Node process, please use safe-eval only with content created by yourself or from trusted sources. User-submitted data should not be run through safe-eval. Thanks @cpcallen for the report.
safe-eval lets you execute JavaScript code without having to use the much discouraged and feared upon eval(). safe-eval has access to all the standard APIs of the V8 JavaScript Engine. By default, it does not have access to the Node.js API, but can be given access using a context object. It is implemented using node's vm module.
Currently, it works only with Node.js, and the JavaScript code must be an expression (something which evaluates to a value).
npm install safe-eval --savevar safeEval = require('safe-eval')safeEval(code, [context], [options])
code is the JavaScript code you want to execute.
context is an object of methods and properties, these methods and properties are interpreted as global objects in code. Be careful about the objects you are passing to the context API, because they can completely defeat the purpose of safe-eval.
options is the options object for the vm executing the code.
// string concatenation
var code = '"app" + "le"'
var evaluated = safeEval(code) // "apple"// math
var code = 'Math.floor(22/7)'
var evaluated = safeEval(code) // 3.142857142857143// JSON
var code = '{name: "Borat", hobbies: ["disco dance", "sunbathing"]}'
var evaluated = safeEval(code) // {name: "Borat", hobbies: ["disco dance", "sunbathing"]}// function expression
var code = '(function square(b) { return b * b; })(5)'
var evaluated = safeEval(code) // 25// no access to Node.js objects
var code = 'process'
safeEval(code) // THROWS!// your own context API - access to Node's process object and a custom function
var code = '{pid: process.pid, apple: a()}'
var context = {
process: process,
a: function () { return 'APPLE' }
}
var evaluated = safeEval(code, context) // { pid: 16987, apple: 'APPLE' }// pass an options object to the vm
var code = 'process'
safeEval(code, {}, { filename: 'myfile.js'}) // myfile.js can be seen in the stacktraceCopyright (c) 2016 Hage Yaapa
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