Syntax error Safely setting object properties with dot notation strings in JavaScript

Safely setting object properties with dot notation strings in JavaScript

You can use lodash's set method to set properties at any level safely. Setting first-level properties are pretty straightforward. Nested property access is tricky and you should use a tested library like lodash for it.

You can set a deeply nested object in the following way −

Example

let _ = require("lodash");
let obj = {
   a: {
      b: {
         foo: "test"
      },
      c: 2
   }
};
_.set(obj, "a.b.foo", "test1");
_.set(obj, "a.c", { test2: "bar" });
console.log(obj);

Output

This will give the output −

{ a: { b: { foo: 'test1' }, c: { test2: 'bar' } } }

You can also write your own setUpdateProp function in the following way −

const setUpdateProp = (object, path, value) => {
   if (path.length === 1) object[path[0]] = value;
      else if (path.length === 0) throw error;
   else {
      if (object[path[0]])
         return setUpdateProp(object[path[0]], path.slice(1), value);
      else {
         object[path[0]] = {};
         return setUpdateProp(object[path[0]], path.slice(1), value);
      }
   }
};

You can use it by passing an array to access the props.

Example

var obj = {
   level1:{
      level2:{
         level3:{
            name: "Foo"
         }
      },
      anotherLevel2: "bar"
   }
};
setUpdateProp(obj, ["level1", "level2"], "FooBar");
console.log(obj);

Output

This will give the output −

{ level1: { level2: 'FooBar', anotherLevel2: 'bar' } }
Updated on: 2019-11-27T10:34:36+05:30

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