Simple application of ES6 arrow functions

Arrow function expressions are new syntactic sugar in ES6. Its syntax is more concise than function expressions, and not have their own this, arguments, superor new.target.

Arrow function expressions are more suitable where anonymous functions are needed, and it cannot be used as a constructor.

You should have seen the power of arrow functions in processing data.

Arrow function in a similar map(), filter(), reduce()and so the need for other functions as arguments to process data in higher-order functions would be good to use.

Read the following code:

FBPosts.filter(function(post) {
  return post.thumbnail !== null && post.shares > 100 && post.likes > 500;
})

We wrote down the filterfunction and tried to ensure readability. Now let's write the same code with arrow functions:

FBPosts.filter((post) => post.thumbnail !== null && post.shares > 100 && post.likes > 500)

This code accomplishes the same task, but becomes shorter and easier to understand.

Now there is a sample problem: use the arrow function syntax to calculate squaredIntegersthe square of positive integers in the array (fractions are not integers).

const realNumberArray = [4, 5.6, -9.8, 3.14, 42, 6, 8.34];

Tip 1: You need to check the realNumberArray using filter () to obtain a positive integer (the decimal point is not an integer).

Tip 2: You need to map the value in the filter () function to the variable squaredIntegers after the map () square operation.

Tip 3: It can be called by chain.

.............................................

Here is the answer:

1 const realNumberArray = [4, 5.6, -9.8, 3.14, 42, 6, 8.34];
2 const squareList = (arr) => {
3   "use strict";
4   const squaredIntegers = arr.filter( (num) => num > 0 && num % parseInt(num) === 0 ).map( (num) => Math.pow(num, 2) );
5   return squaredIntegers;
6 };
7 const squaredIntegers = squareList(realNumberArray);
8 console.log(squaredIntegers);

Output result:

Part of the content is from learn.freecodecamp.one

Simple application of ES6 arrow functions

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