You can not select more than 25 topics
			Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
		
		
		
		
		
			
		
			
				
					64 lines
				
				1.4 KiB
			
		
		
			
		
	
	
					64 lines
				
				1.4 KiB
			| 
											3 years ago
										 | # 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')); | ||
|  | ``` |