Context-preserving eval

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The article you linked contains a crazy approach that actally works: during each eval() call, we create a new closure inside that eval scope and export it so that to we can use it evaluate the next statement.

var __EVAL = s => eval(`void (__EVAL = ${__EVAL.toString()}); ${s}`);

function evaluate(expr) {
    try {
        const result = __EVAL(expr);
        console.log(expr, '===>', result)
    } catch(err) {
        console.log(expr, 'ERROR:', err.message)
    }
}

evaluate('var ten = 10')
evaluate('function cube(x) { return x ** 3 }')
evaluate('ten + cube(3)')
evaluate('console.log("SIDE EFFECT")')
evaluate('let twenty = 20')
evaluate('twenty + 40') // NO PROBLEM :D

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