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A proposal to addArray.prototype.filterReject.

constarray=[1,2,3,4,5];// filter keeps the items that return true.array.filter(i=>(i<3));// => [1, 2];// filterReject removes the items that return true.array.filterReject(i=>(i<3));// => [3, 4, 5];

• Justin Ridgewell (@jridgewell)

CurrentStage: 1

Array.p.filter is confusing. I constantly have to ask myself "am Ikeeping, or filtering out the current item?".

"Keeping"

Implies that returningtrue would keep the current item.

"Filtering out"

Implies that returningtrue would remove the current item.

Array.p.filter acts as "keeping". But when I think of the word"filter", I think of "filtering out". So every time that I attempt towrite an array filter, I end up writing the opposite of what I intended.

Array.p.filterReject attempts to fix this confusion. By providing aclearly named filtering function that matches my intuition, I'm ablewhat will happen when callingfilterReject. And because it exists, I'mable to assume thatfilter does something different, so it must be"keep" version.

A polyfill is available in thecore-js library. You can find it in theECMAScript proposals section.

• Supporting Data from HTTP Archive and GitHub Archive
• What shouldfilterOut be called?
• Shouldpartition be included?

• Ruby
  • Array#select
  • Array#reject
  • Array#partition
• Underscore
  • _.select (aliased to _.filter)
  • _.reject
  • _.partition
• Lodash
  • _.reject (700k downloads/week)
  • _.partition (18k downloads/week)