chain functions
lets asume that we have an array of object
and you want to make few operation on the array like
filter , map , sort
so one option will be straightforward
run each time on every operation
const arr = [{ name: itay, age: 10 }, { name: sam, age: 20 }, { name: jett, age: 30 }, { name: bob, age: 40 }]
//filter the obkect with age under 10
const filtering = ({ age }) => age > 10
filterdArr = arr.filter(filtering)
// abount the sorting - if the function return negetive value then a will be befora b
//and if the funtion return positive number then b will be before a
const sorting = (a, b) => a.age - b.age
sortedArr = filterdArr.sort(sorting)
//refactor the object , changed age to myAge
const mapping = ({ name, age }) => ({ name, myAge: age })
mapedArr = sortedArr.map(mapping)
console.log(mapedArr)
the second option will be to chain the funtions
like that
console.log(
arr.filter(filtering)
.sort(sorting)
.map(mapping))
and the result will be the same
[
{ name: 'jett', myAge: 30 },
{ name: 'bob', myAge: 40 },
{ name: 'sam', myAge: 55 }
]
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