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Accessing nested JavaScript objects with string key
You can use lodash's get method to get properties at any level safely. Getting first-level properties is pretty straightforward. Nested property access is tricky and you should use a tested library like lodash for it.
You can access a deeply nested object in the following way −
Example
let _ = require("lodash");
let obj = {
a: {
b: {
foo: "test"
},
c: 2
}
};
console.log(_.get(obj, "a.b.foo"));
console.log(_.get(obj, "a.c"));
console.log(_.get(obj, "a.test"));
console.log(_.get(obj, "a.test.x"));Output
This will give the output −
test 2 undefined undefined
You can also write your own getProp function in the following way −
const getProp = (object, path) => {
if (path.length === 1) return object[path[0]];
else if (path.length === 0) throw error;
else {
if (object[path[0]]) return getProp(object[path[0]], path.slice(1));
else {
object[path[0]] = {};
return getProp(object[path[0]], path.slice(1));
}
}
};You can use it by passing an array to access the props.
Example
var obj = {
level1:{
level2:{
level3:{
name: "Foo"
}
},
anotherLevel2: "bar"
}
};
console.log(getProp(obj, ["level1", "level2"]));Output
This will give the output −
{level3: {name: "Foo"}}
Updated on: 27-Nov-2019
2K+ Views
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