Swap-Aggregator-Subgraph/node_modules/pull-stream/throughs/unique.js
Richa-iitr d211083153 Revert "Revert "added handler""
This reverts commit c36ee8c5ca.
2022-07-03 07:30:05 +05:30

19 lines
428 B
JavaScript

'use strict'
function id (e) { return e }
var prop = require('../util/prop')
var filter = require('./filter')
//drop items you have already seen.
module.exports = function unique (field, invert) {
field = prop(field) || id
var seen = {}
return filter(function (data) {
var key = field(data)
if(seen[key]) return !!invert //false, by default
else seen[key] = true
return !invert //true by default
})
}