I am trying to update a nested JSON which is given as an input, e.g.:
{
"doc": {
"a1": {
"b1": 1,
"b2": [
"one",
"two"
]
},
"a2": "xyz"
}
}
The JSON structure is not known.
Field to update is an input string eg: "doc.a2" or "doc.a1.b1" or "doc.a1.b2"
In addition to the path, the old value and a new value is also given as input. If the value in the path matches the old value, I want to update it with new value.
I tried with eval() and seems possible like
if path is "doc.a1.b1", then eval(doc['a1']['b1']='new value');
But using eval may lead to security issues. Is there a better way to achieve this?
try this
var input1 = "doc.a2";
val1 = "val1";
updateVal(obj, input1, val1);
console.log("val1", obj);
function updateVal(obj, input, val) {
let props = input.split(".");
let currObj = obj;
let index = 0;
for (index = 0; index < props.length - 1; index++) {
currObj = currObj[props[index]];
};
currObj[props[index]] = val;
};
Assuming you don't want to rely on a third party library, here is a 5-line proposal (it may need refinement to tackle corner cases such as invalid given path, depending on how you want to handle those cases, e.g. error, or create the path).
// given: ///////////////////////////////////
const obj = {
"doc": {
"a1": {
"b1": 1,
"b2": [
"one",
"two"
]
},
"a2": "xyz"
}
}
const str = "doc.a1.b2"
const newValue = ["three"]
// do: ///////////////////////////////////////
const keys = str.split(".")
let ptr = obj
while(keys.length>1)
ptr = ptr[keys.shift()]
ptr[keys.shift()] = newValue
// result: ///////////////////////////////////
console.log(obj)