https://github.com/remy/undefsafe
Simple *function* for retrieving deep object properties without getting "Cannot read property 'X' of undefined"
https://github.com/remy/undefsafe
Last synced: 6 months ago
JSON representation
Simple *function* for retrieving deep object properties without getting "Cannot read property 'X' of undefined"
- Host: GitHub
- URL: https://github.com/remy/undefsafe
- Owner: remy
- License: mit
- Created: 2014-01-08T14:25:39.000Z (over 11 years ago)
- Default Branch: master
- Last Pushed: 2021-10-17T09:35:43.000Z (almost 4 years ago)
- Last Synced: 2025-03-29T04:09:42.347Z (6 months ago)
- Language: JavaScript
- Size: 46.9 KB
- Stars: 72
- Watchers: 5
- Forks: 9
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# undefsafe
Simple *function* for retrieving deep object properties without getting "Cannot read property 'X' of undefined"
Can also be used to safely set deep values.
## Usage
```js
var object = {
a: {
b: {
c: 1,
d: [1,2,3],
e: 'remy'
}
}
};
console.log(undefsafe(object, 'a.b.e')); // "remy"
console.log(undefsafe(object, 'a.b.not.found')); // undefined
```
Demo: [https://jsbin.com/eroqame/3/edit?js,console](https://jsbin.com/eroqame/3/edit?js,console)
## Setting
```js
var object = {
a: {
b: [1,2,3]
}
};
// modified object
var res = undefsafe(object, 'a.b.0', 10);
console.log(object); // { a: { b: [10, 2, 3] } }
console.log(res); // 1 - previous value
```
## Star rules in paths
As of 1.2.0, `undefsafe` supports a `*` in the path if you want to search all of the properties (or array elements) for a particular element.
The function will only return a single result, either the 3rd argument validation value, or the first positive match. For example, the following github data:
```js
const githubData = {
commits: [{
modified: [
"one",
"two"
]
}, /* ... */ ]
};
// first modified file found in the first commit
console.log(undefsafe(githubData, 'commits.*.modified.0'));
// returns `two` or undefined if not found
console.log(undefsafe(githubData, 'commits.*.modified.*', 'two'));
```