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ECMAScript Expressions parser and static eval

Home Page: https://ianchi.github.io/ESpression-tester/

License: MIT License

TypeScript 99.45% JavaScript 0.55%

jsonpath ast ecmascript-expressions-parser static-eval esprima expression expression-evaluator

espression's People

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espression's Issues

ES5Eval was renamed?

The example in README doesn't run. It seems that ES5Eval had been renamed to ES5StaticEval. BTW, is there a complete doc for the API?

A better error message when accessing missing methods

https://ianchi.github.io/ESpression-tester/
Context

{"a": 1}

Expression

a.match()

Parsed AST

 "can't access property \"apply\", s is undefined"

Two problems:

It would be nice to have a better error message e.g. can't call function, a.match is undefined.
Why changing context would affect parsed AST? I thought it is only used while evaluating the expression.

Question/docs: Is this any safer than eval'ing an unstrusted string directly?

My use case is that I would like to allow admin users of a service to define expressions that would evaluate objects to either pass or reject them. The expression would be evaluated server-side.

From the readme, it's not really clear whether passing an expression through this library is intended to make evaluating such an expression safe?

The bundle is large comparing to jsep + expression-eval

https://github.com/eight04/espression-bundle
https://github.com/eight04/expression-eval-bundle

filename\library	espression	expression-eval
.js	55KB	24KB
.min.js	28KB	7KB

BTW, what I need is jsep with regexp literal. Should I just use EricSmekens/jsep#78 instead?

Async function eval support

Thanks for awesome library.

I've found that there's no async function support, similar to donmccurdy/expression-eval. any plans to add it?

Provide a way to collect useful information (e.g. finding the names of variables) while parsing

I used to use jsep and I am switching to ESpression. I had my own eval function, which is already provided by ESpression, but I also had a function to find the names of variables used in an AST. This is useful to reevaluate some expressions when the referenced variables change. Could this feature be useful for other developers and be implemented in the module? Maybe by providing an optional parameter to parse that could collect some information, or call a handler for each visited node.

For information, this was my implementation to walk the AST and gather variable names:

function _vars(set, ...nodes)
{
    for (let node of nodes)
        switch (node.type) {

            case 'Literal':
            case 'ThisExpression':
                break;

            case 'Compound':
                _vars(set, ...node.body);
                break;

            case 'ArrayExpression':
                _vars(set, ...node.elements);
                break;

            case 'UnaryExpression':
                _vars(set, node.argument);
                break;

            case 'LogicalExpression':
            case 'BinaryExpression':
                _vars(set, node.left, node.right);
                break;

            case 'ConditionalExpression':
                _vars(set, node.test, node.consequent, node.alternate);
                break;

            case 'CallExpression':
                _vars(set, node.callee, ...node.arguments);
                break;

            case 'Identifier':
                set.add(node.name);
                break;

            case 'MemberExpression':
                switch (node.object.type) {
                    case 'Identifier':
                        set.add(node.object.name);
                        break;
                    case 'ThisExpression':
                        set.add(node.property.name);
                        break;
                    case 'MemberExpression':
                        _vars(set, node.object);
                        break;
                    default:
                        throw new Error(`Unhandled member expression ${node.object.type}`);
                }
                break;

            default:
                throw new Error(`unhandled node type ${node.type}`);
        }
}

export function vars(ast)
{
    const set = new Set();
    _vars(set, ast);
    return set;
}

ianchi / espression Goto Github PK

espression's People

Contributors

Stargazers

Watchers

espression's Issues

ES5Eval was renamed?

A better error message when accessing missing methods

Question/docs: Is this any safer than eval'ing an unstrusted string directly?

The bundle is large comparing to jsep + expression-eval

Async function eval support

Provide a way to collect useful information (e.g. finding the names of variables) while parsing

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