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    static-eval
    DefinitelyTyped icon, indicating that this package has TypeScript declarations provided by the separate @types/static-eval package

    2.0.0 • Public • Published

    static-eval

    evaluate statically-analyzable expressions

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    build status

    example

    var evaluate = require('static-eval');
    var parse = require('esprima').parse;
    
    var src = process.argv[2];
    var ast = parse(src).body[0].expression;
    
    console.log(evaluate(ast));

    If you stick to simple expressions, the result is statically analyzable:

    $ node '7*8+9'
    65
    $ node eval.js '[1,2,3+4*5-(5*11)]'
    [ 1, 2, -32 ]
    

    but if you use statements, undeclared identifiers, or syntax, the result is no longer statically analyzable and evaluate() returns undefined:

    $ node eval.js '1+2+3*n'
    undefined
    $ node eval.js 'x=5; x*2'
    undefined
    $ node eval.js '5-4*3'
    -7
    

    You can also declare variables and functions to use in the static evaluation:

    var evaluate = require('static-eval');
    var parse = require('esprima').parse;
    
    var src = '[1,2,3+4*10+n,foo(3+5),obj[""+"x"].y]';
    var ast = parse(src).body[0].expression;
    
    console.log(evaluate(ast, {
        n: 6,
        foo: function (x) { return x * 100 },
        obj: { x: { y: 555 } }
    }));

    methods

    var evaluate = require('static-eval');

    evaluate(ast, vars={})

    Evaluate the esprima-parsed abstract syntax tree object ast with an optional collection of variables vars to use in the static expression resolution.

    If the expression contained in ast can't be statically resolved, evaluate() returns undefined.

    install

    With npm do:

    npm install static-eval
    

    license

    MIT

    Install

    npm i static-eval@2.0.0

    Version

    2.0.0

    License

    MIT

    Last publish

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