| # 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')); | |
| ``` | |