[JS]Change multi level object value

Question

var obj = {
    a:{
        value: 1
    }
}

var str = 'a.value';

obj[str] = 'work';
console.log(obj);

I have this code, I need to change the value of the object using the string

Answer 1

You need to split the path and use it as keys for the object.

If the key is not an object, a new object is created.

 function set(obj, path, value) { var p = path.split('.'), last = p.pop(); p.reduce(function (o, k) { if (typeof o[k] !== 'object') { o[k] = {}; } return o[k]; }, obj)[last] = value; } var obj = { a: { value: 1 } }; set(obj, 'a.value', 'work'); set(obj, 'b.value', 42); set(obj, 'c', 'c'); console.log(obj); set(obj, 'c.value', 'work'); console.log(obj); 

ES6

 function set(obj, path, value) { var p = path.split('.'), last = p.pop(); p.reduce((o, k) => o[k] = typeof o[k] === 'object' ? o[k] : {}, obj)[last] = value; } var obj = { a: { value: 1 } }; set(obj, 'a.value', 'work'); set(obj, 'b.value', 42); set(obj, 'c', 'c'); console.log(obj); set(obj, 'c.value', 'work'); console.log(obj); 

Answer 2

Solution with recursion

 var obj = { a: { value: 1 } } var str = 'a.value'; function change(obj, prop, newValue) { var a = prop.split('.'); return (function f(o, v, i) { if (i == a.length - 1) { o[a[i]] = v; return o; } return f(o[a[i]], v, ++i); })(obj, newValue, 0); } var result = change(obj, str, 'work'); console.log(JSON.stringify(obj, 0, 2)); 

Answer 3

您可以尝试使用eval()

eval('obj.'+str + '="work"');