如何使用文字 object、javascript 中的键创建变量

Question

In an exercise, I have to make a variable called "fullAddress" that contains everything in a given literal object except for the first key.

I found a solution that sort of works, but I feel like there is a better way to do it. Also, I can't figure out how to efficiently put space between the values in the variable.

The exercise says the final result should look something like this:

39 Johnson Ave, Brooklyn, NY, 11206

But mine looks like this:

39 Johnson AveBrooklynNY11206

---

Literal Object provided in exercise:

const restaurant = {
    name: 'Ichiran Ramen',
    address: `${Math.floor(Math.random() * 100) + 1} Johnson Ave`,
    city: 'Brooklyn',
    state: 'NY',
    zipcode: '11206',
}

My solution:

let fullAddress = restaurant.address + restaurant.city + restaurant.state + restaurant.zipcode; 

Answer 1

Given an array of strings, you can use values.join(', ') to put commas between the values cleanly. Then you could do eg [restaurant.address, restaurant.city, restaurant.state, restaurant.zipcode].join(', ') .

If you wanted to do this more generically for any object, you could use Object.values(restaurant).slice(1).join(', ') to dynamically get all values after the first and comma delimit them.

In this case though, I think it makes the most sense to just explicitly append with commas since it's an address format (maybe you don't want a space after the zip code for example), so something like restaurant.address + ', ' + restaurant.city +...

Answer 2

Regarding spaces (and commas), you can use a template string as done for restaurant.address .

 const restaurant = { name: 'Ichiran Ramen', address: `${Math.floor(Math.random() * 100) + 1} Johnson Ave`, city: 'Brooklyn', state: 'NY', zipcode: '11206', }; let fullAddress = `${restaurant.address}, ${restaurant.city}, ${restaurant.state}, ${restaurant.zipcode}`; console.log(fullAddress); // 39 Johnson Ave, Brooklyn, NY, 11206

Next, notice we're actually joining all the address-parts with the same delimiter: ', ' . This means we can use [].join() instead.

 const restaurant = { name: 'Ichiran Ramen', address: `${Math.floor(Math.random() * 100) + 1} Johnson Ave`, city: 'Brooklyn', state: 'NY', zipcode: '11206', }; let addressParts = [restaurant.address, restaurant.city, restaurant.state, restaurant.zipcode]; let fullAddress = addressParts.join(', '); console.log(fullAddress); // 39 Johnson Ave, Brooklyn, NY, 11206

Lastly, (if you want to get fancy), note that restaurant. is repeated. This can be avoided with [].map() .

 const restaurant = { name: 'Ichiran Ramen', address: `${Math.floor(Math.random() * 100) + 1} Johnson Ave`, city: 'Brooklyn', state: 'NY', zipcode: '11206', }; let fullAddress = ['address', 'city', 'state', 'zipcode'].map(key => restaurant[key]).join(', '); console.log(fullAddress); // 39 Johnson Ave, Brooklyn, NY, 11206

Answer 3

You can take out all the values from the restaurant object, remove the first element and then use join to get the desired string

 const restaurant = { name: 'Ichiran Ramen', address: `${Math.floor(Math.random() * 100) + 1} Johnson Ave`, city: 'Brooklyn', state: 'NY', zipcode: '11206', } const fullAddress = Object.values(restaurant).slice(1).join(', '); console.log(fullAddress);