Question

for (var i in variables) {
    eval('var ' + i + ' = variables[i]');
}

Basically, I want to transfer variables properties to local variables.

Is there an alternative to using eval()

Or which of these is better:

1.

var _ = variables;
for (var i = 0; i < 100000; i++) {
    _.test1();
    _.test2();
    _.test3();
}

2.

with (variables) {
    for (var i = 0; i < 100000; i++) {
        test1();
        test2();
        test3();
    }
}

3.

var test1 = variables.test1,
    test2 = variables.test2,
    test3 = variables.test3;
for (var i = 0; i < 100000; i++) {
    test1();
    test2();
    test3();
}

4.

for (var i in variables) eval('var ' + i + ' = variables[i]');
for (var i = 0; i < 100000; i++) {
    test1();
    test2();
    test3();
}

Answer 1

Well, I’ll post the answer myself.

No.

There is no way to set local variables without knowing the name of the variable without using eval()…

…But using local variables (option 3) is the best way.