操作员在严格模式下更换“with”

Question

I have string value which entered user, for example the variable f.

f = "1/log(x)";

In vanilla JavaScript, i used operator with:

f = "with (Math) {" + f + "}";

The code work excellent in vanilla javascript, but i use Vue js and have problems in strict mode. I don't know how replace this operator. Who faced with this problem please answer me.

I try this:

            let math = Math
            math.f = f
            console.log(f)

But nothing working.

Answer 1

Basically with is not recommended to be used because it can cause issues in programs. So what are your options?

define a bunch of globals

 const sqrt = Math.sqrt const log = Math.log const test1 = new Function("a","return sqrt(a)") const test2 = new Function("b","return log(b)") console.log(test1(4)) console.log(test2(100)) 

Other option is to do the replacements with a reg exp

 const fixMath = eq => eq.replace(/(sqrt|log|pow)/g,'Math.$1') const test1 = new Function("a", fixMath("return sqrt(a)")) const test2 = new Function("b", fixMath("return log(b)")) const test3 = new Function("a", "b", fixMath("return pow(a, b)")) const test4 = new Function("a", "b", fixMath("return sqrt(pow(a, 2) + pow(b, 2))")) console.log(test1(4)) console.log(test2(100)) console.log(test3(10, 3)) console.log(test4(3, 3))