107 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
		
		
			
		
	
	
			107 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
|   | --- | ||
|  | id: 587d7b89367417b2b2512b4a | ||
|  | title: Use Destructuring Assignment to Assign Variables from Nested Objects | ||
|  | challengeType: 1 | ||
|  | forumTopicId: 301214 | ||
|  | dashedName: use-destructuring-assignment-to-assign-variables-from-nested-objects | ||
|  | --- | ||
|  | 
 | ||
|  | # --description--
 | ||
|  | 
 | ||
|  | You can use the same principles from the previous two lessons to destructure values from nested objects. | ||
|  | 
 | ||
|  | Using an object similar to previous examples: | ||
|  | 
 | ||
|  | ```js | ||
|  | const user = { | ||
|  |   johnDoe: {  | ||
|  |     age: 34, | ||
|  |     email: 'johnDoe@freeCodeCamp.com' | ||
|  |   } | ||
|  | }; | ||
|  | ``` | ||
|  | 
 | ||
|  | Here's how to extract the values of object properties and assign them to variables with the same name: | ||
|  | 
 | ||
|  | ```js | ||
|  | const { johnDoe: { age, email }} = user; | ||
|  | ``` | ||
|  | 
 | ||
|  | And here's how you can assign an object properties' values to variables with different names: | ||
|  | 
 | ||
|  | ```js | ||
|  | const { johnDoe: { age: userAge, email: userEmail }} = user; | ||
|  | ``` | ||
|  | 
 | ||
|  | # --instructions--
 | ||
|  | 
 | ||
|  | Replace the two assignments with an equivalent destructuring assignment. It should still assign the variables `lowToday` and `highToday` the values of `today.low` and `today.high` from the `LOCAL_FORECAST` object. | ||
|  | 
 | ||
|  | # --hints--
 | ||
|  | 
 | ||
|  | You should remove the ES5 assignment syntax. | ||
|  | 
 | ||
|  | ```js | ||
|  | assert( | ||
|  |   !code.match(/lowToday = LOCAL_FORECAST\.today\.low/g) && | ||
|  |     !code.match(/highToday = LOCAL_FORECAST\.today.high/g) | ||
|  | ); | ||
|  | ``` | ||
|  | 
 | ||
|  | You should use destructuring to create the `lowToday` variable. | ||
|  | 
 | ||
|  | ```js | ||
|  | assert( | ||
|  |   code.match( | ||
|  |     /(var|const|let)\s*{\s*today\s*:\s*{\s*(low\s*:\s*lowToday[^}]*|[^,]*,\s*low\s*:\s*lowToday\s*)}\s*}\s*=\s*LOCAL_FORECAST(;|\s+|\/\/)/g | ||
|  |   ) | ||
|  | ); | ||
|  | ``` | ||
|  | 
 | ||
|  | You should use destructuring to create the `highToday` variable. | ||
|  | 
 | ||
|  | ```js | ||
|  | assert( | ||
|  |   code.match( | ||
|  |     /(var|const|let)\s*{\s*today\s*:\s*{\s*(high\s*:\s*highToday[^}]*|[^,]*,\s*high\s*:\s*highToday\s*)}\s*}\s*=\s*LOCAL_FORECAST(;|\s+|\/\/)/g | ||
|  |   ) | ||
|  | ); | ||
|  | ``` | ||
|  | 
 | ||
|  | `lowToday` should be equal to `64` and `highToday` should be equal to `77`. | ||
|  | 
 | ||
|  | ```js | ||
|  | assert(lowToday === 64 && highToday === 77); | ||
|  | ``` | ||
|  | 
 | ||
|  | # --seed--
 | ||
|  | 
 | ||
|  | ## --seed-contents--
 | ||
|  | 
 | ||
|  | ```js | ||
|  | const LOCAL_FORECAST = { | ||
|  |   yesterday: { low: 61, high: 75 }, | ||
|  |   today: { low: 64, high: 77 }, | ||
|  |   tomorrow: { low: 68, high: 80 } | ||
|  | }; | ||
|  | 
 | ||
|  | // Only change code below this line | ||
|  |    | ||
|  | const lowToday = LOCAL_FORECAST.today.low; | ||
|  | const highToday = LOCAL_FORECAST.today.high; | ||
|  | 
 | ||
|  | // Only change code above this line | ||
|  | ``` | ||
|  | 
 | ||
|  | # --solutions--
 | ||
|  | 
 | ||
|  | ```js | ||
|  | const LOCAL_FORECAST = { | ||
|  |   yesterday: { low: 61, high: 75 }, | ||
|  |   today: { low: 64, high: 77 }, | ||
|  |   tomorrow: { low: 68, high: 80 } | ||
|  | }; | ||
|  |   | ||
|  | const { today: { low: lowToday, high: highToday }} = LOCAL_FORECAST; | ||
|  | ``` |