Chrome App: Doing maths from a string

问题

I have a basic Chrome App that I'm building that constructs strings like this:

"1 + 4 - 3 + -2"

Seeing as you can't use eval() in Chrome Apps, how can I get the answer to a string like so?

eg. If this was just a normal webpage I would use something like this:

var question = {
  text: "1 + 4 - 3 + -2",
  answer: eval(this.text)
}

Is there any possible way of replacing eval() with something else to answer a string like question.text?

回答1:

Try modifying string to

"+1 +4 -3 -2"

utilizing String.prototype.split() , Array.prototype.reduce() , Number()

var question = {
  text: "+1 +4 -3 -2",
  answer: function() {
            return this.text.split(" ")
                   .reduce(function(n, m) {
                     return Number(n) + Number(m)
                   })
          }
};

console.log(question.answer())

回答2:

Try this

var question = {
  text: "1 + 4 - 3 + -2",
  answer: eval(ans(question.text))
}
console.log('Text : '+question.text);
console.log('answer : '+question.answer);

Used String replace method

function ans(str){
var s = str.replace(/\s/g, '')
console.log('S : '+s);
return s;
}

来源：https://stackoverflow.com/questions/32982719/chrome-app-doing-maths-from-a-string