64 lines
1.4 KiB
Plaintext
64 lines
1.4 KiB
Plaintext
# 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'));
|
|
```
|