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SHaon
SHaon

Posted on

New Usefull JavaScript Tips For Everyone

*Old Ways *

 const getPrice = (item) => {
  if(item==200){return 200} 
   else if (item==500){return 500}
   else if (item===400) {return 400}
   else {return 100}
}

console.log(getPrice(foodName));

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New Ways

const prices = {
 food1 : 100,
 food2 : 200,
 food3 : 400,
 food4 : 500
}

const getPrice = (item) => {
 return prices[item]
}

console.log(getPrice(foodName))
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Hope you like my new tricks :D

follow my github account

Top comments (3)

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pierrewahlberg profile image
Pierre Vahlberg • Edited on

For this specific use case and similar "lookups", check out Map and Set in the MDN docs. They build on the dictionary/hash map which is essential JS functionality, now with a nice interface.

Note that the use cases are different, they are both iterable (for ...of.. etc) and that their purpose is value lookup or keeping track of values

Like this

var allowedPrices = new Set([100, 200, 300])
var price = allowedPrices.has(233) || 100; // gives 100
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Using large lists this approach outperforms and array version by far and is a lot cleaner IMO.

An example for map could be

var map = new Map([
    [ 100, "cheap" ],
    [ 200, "afforfable"],
    [ 300, "expensive"],
])

var price = 200;
var priceLabel = map.get(price) || "untagged"; // affordable
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developer.mozilla.org/en-US/docs/W...

developer.mozilla.org/en-US/docs/W...

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pierrewahlberg profile image
Pierre Vahlberg

Oh, I did not mean to criticize but to educate! 😊 keep writing and keep learning πŸ™

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jonrandy profile image
Jon Randy • Edited on

You might want to improve the 'old ways' example. Currently you could replace the function with this:

const getPrice = item => [200, 400, 500].includes(item) ? item : 100
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Ideally, the first example should have identical functionality to the second. There is also an issue with the second example - it will return undefined if it doesn't know the item.

"I made 10x faster JSON.stringify() functions, even type safe"

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