Javascript-obfuscator: transformObjectKeys=true causes obfuscator to crash with "TypeError: Cannot read property 'type' of undefined" if input code contains object spread operator

Created on 19 Nov 2019 · 6Comments · Source: javascript-obfuscator/javascript-obfuscator

var JavaScriptObfuscator = require('javascript-obfuscator');

var obfuscationResult = JavaScriptObfuscator.obfuscate(
    `
        var obj1={
        firstname:'John',
        lastname:'Smith'
    };
    var obj2={
        age:40,
        country:'USA'
    }
    var user={...obj1, ...obj2}
    console.log(user);

    `,
    {
        transformObjectKeys: true,
    }
);

console.log(obfuscationResult.getObfuscatedCode());

Expected Behavior

The normal ouput of this program is:

{firstname: "John", lastname: "Smith", age: 40, country: "USA"}

Current Behavior

The current behavior is:

/Users/vincent/dev/packager/node_modules/javascript-obfuscator/dist/webpack:/JavaScriptObfuscator/src/node/NodeGuards.ts:270
        return node.type === NodeType.ObjectPattern;
                    ^
TypeError: Cannot read property 'type' of undefined
    at Function.type (/Users/vincent/dev/packager/node_modules/javascript-obfuscator/dist/webpack:/JavaScriptObfuscator/src/node/NodeGuards.ts:270:21)
    at Function.isObjectPatternNode (/Users/vincent/dev/packager/node_modules/javascript-obfuscator/dist/webpack:/JavaScriptObfuscator/src/node-transformers/converting-transformers/properties-extractors/AbstractPropertiesExtractor.ts:86:27)
    at t.isProhibitedPattern (/Users/vincent/dev/packager/node_modules/javascript-obfuscator/dist/webpack:/JavaScriptObfuscator/src/node-transformers/converting-transformers/properties-extractors/AbstractPropertiesExtractor.ts:120:45)
    at t.extractPropertiesToExpressionStatements (/Users/vincent/dev/packager/node_modules/javascript-obfuscator/dist/webpack:/JavaScriptObfuscator/src/node-transformers/converting-transformers/properties-extractors/AbstractPropertiesExtractor.ts:187:14)
    at transformObjectExpressionNode (/Users/vincent/dev/packager/node_modules/javascript-obfuscator/dist/webpack:/JavaScriptObfuscator/src/node-transformers/converting-transformers/properties-extractors/VariableDeclaratorPropertiesExtractor.ts:42:21)
    at t.extract (/Users/vincent/dev/packager/node_modules/javascript-obfuscator/dist/webpack:/JavaScriptObfuscator/src/node-transformers/converting-transformers/ObjectExpressionKeysTransformer.ts:104:36)
    at transformNode (/Users/vincent/dev/packager/node_modules/javascript-obfuscator/dist/webpack:/JavaScriptObfuscator/src/node-transformers/converting-transformers/ObjectExpressionKeysTransformer.ts:67:33)
    at Controller.visitorFunction (/Users/vincent/dev/packager/node_modules/javascript-obfuscator/dist/webpack:/JavaScriptObfuscator/src/node-transformers/TransformersRunner.ts:111:55)
    at Controller.__execute (/Users/vincent/dev/packager/node_modules/estraverse/estraverse.js:397:31)
    at Controller.replace (/Users/vincent/dev/packager/node_modules/estraverse/estraverse.js:637:27)

Steps to Reproduce (for bugs)

create a file with the above code in a npm project
run the code
bug occurs

Your Environment

No related to environment, even on https://obfuscator.io/ it happens as well, the website does not obfuscate the code and displays TypeError: Cannot read property 'type' of undefined