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    argencoders-notevil

    2.5.0¬†‚Äʬ†Public¬†‚Äʬ†Published

    notevil

    Evalulate javascript like the built-in javascript eval() method but safely.

    This module uses esprima to parse the javascript AST then walks each node and evaluates the result.

    Like built-in eval, the result of the last expression will be returned. Unlike built-in, there is no access to global objects, only the context that is passed in as the second object.

    Built in types such as Object and String are still available, but they are wrapped so that any changes to prototypes are contained in the eval instance.

    NPM

    Example

    var safeEval = require('notevil')
     
    // basic math
    var result = safeEval('1+2+3')
    console.log(result) // 6
     
    // context and functions
    var result = safeEval('1+f(2,3)+x', {
      x: 100, 
      f: function(a,b){
        return a*b
      }
    })
    console.log(result) // 107
     
    // multiple statements, variables and if statements
    var result = safeEval('var x = 100, y = 200; if (x > y) { "cats" } else { "dogs" }')
    console.log(result) // dogs
     
    // inner functions
    var result = safeEval('[1,2,3,4].map(function(item){ return item*100 })')
    console.log(result) // [100, 200, 300, 400]

    Updating context from safeEval

    var context = { x: 1, obj: {y: 2} }
     
    // update context global
    safeEval('x = 300', context)
    console.log(context.x) // 300
     
    // update property on object
    safeEval('obj.y = 300', context)
    console.log(context.obj.y) // 300

    Creating functions

    var func = safeEval.Function('param', 'return param * 100')
    var result = func(2)
    console.log(result) // 200

    Tracing errors

    A .trace property is available on error objects generated by code running inside of the sandbox. It contains an array containing the esprima node stack which has a loc property, allowing you to get the line and column where the error occurred.

    try {
      safeEval('throw "some error"')
    } catch (ex) {
      ex.trace //=> [...esprimaAstTrace]
      ex.trace[0].loc.start.line //=> 1
    }
    

    Install

    npm i argencoders-notevil

    DownloadsWeekly Downloads

    1

    Version

    2.5.0

    License

    MIT

    Unpacked Size

    37.5 kB

    Total Files

    11

    Last publish

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