如何将字符串转换为模板字符串

Question

Let's say I have:

 var json = '{"greetings": "`${greetings}`"}';
 var obj = JSON.parse(json);
 var template = obj.greetings; //`${greetings}`

 var greetings = 'hello';

how to evaluate template to get hello?

Answer 1

Since JSON.parse() returns obj.greetings as string, you can use eval() to run the string as js. So just:

var json = '{"greetings": "`${greetings}`"}';
var obj = JSON.parse(json);
var template = eval(obj.greetings); //`${greetings}`

var greetings = 'hello';
console.log(greetings)// hello

But eval() should always be used with caution as string maybe entered through user input.

Edit:

The above code with eval returns undefined . This is because JavaScript Hoisting doesn't work for initialized variable.

So we surely need to move the initialisation var greetings = 'hello'; at the top. Solution without eval() :

Apply template string to the whole string.

 var greetings = 'hello'; var json = `{"greetings": "${greetings}"}`; var obj = JSON.parse(json); var template = obj.greetings; //`${greetings}` console.log(template); //hello