如何将 json 的值从字符串转换为 javascript 中的 object？

Question

I'm using angular 8 and I have a json like this:

     validations: [
    {
      name: "required",
      validator: "Validators.required",
      message: "required"
    }

I dont know How I convert "Validators.required" (string) to Validators.required?

Answer 1

I think what you want to do is you that have var Validators = {required: true} as global variable and you want to access it from the string from validations array.

You can access global var Validators with window.Validators or window["Validators"] .

To access Validators.required you can use window.Validators.required or window["Validators"]["required"] .

For that you can split "Validators.required" with . and use reduce to return window["Validators"]["required"] value as per below code.

 var Validators = { required: true }; let validations = [{ name: "required", validator: "Validators.required", message: "required" }]; let result = validations[0].validator.split('.').reduce((a, i) => a[i], window); // <- Use window to access global variable. console.log(result);

---

Or if you are having var Validators = {required: true} inside any component then you can use object of that component with second parameter of reduce .

For example you have component object which has Validators = {required: true} then use code like below.

 let component = { Validators: { required: true } }; let validations = [{ name: "required", validator: "Validators.required", message: "required" }]; let result = validations[0].validator.split('.').reduce((a, i) => a[i], component); console.log(result);

Answer 2

You can use js function JSON.parse()

While parsing check for a valid json. By using JSON.parse() in a try catch block

try { JSON.parse(json); return true; } catch (e) { return false; }}

var object = JSON.parse('validJSON')