When you write code like the following
const expr = "2 -3";
console.log(evaluate(expr)); // 2
You will get 2 instead of -1, this is because the tokenizer parses -3 into a number instead of an operator and a number.
If you want to get -1,please add a space before 3, like below
const expr = "2 - 3";
console.log(evaluate(expr)); // -1
When you write code like the following
You will get
2instead of-1, this is because the tokenizer parses-3into a number instead of an operator and a number.If you want to get
-1,please add a space before3, like below