ce4c83ff
 wxy
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'use strict';
/**
* Concat and flattens non-null values.
* Ex: concat(1, undefined, 2, [3, 4]) = [1, 2, 3, 4]
*/
function concat() {
const args = Array.from(arguments).filter(e => e != null);
const baseArray = Array.isArray(args[0]) ? args[0] : [args[0]];
return Array.prototype.concat.apply(baseArray, args.slice(1));
}
/**
* Dedupes array based on criterion returned from iteratee function.
* Ex: uniqueBy(
* [{ id: 1 }, { id: 1 }, { id: 2 }],
* val => val.id
* ) = [{ id: 1 }, { id: 2 }]
*/
function uniqueBy(arr, fun) {
const seen = {};
return arr.filter(el => {
const e = fun(el);
return !(e in seen) && (seen[e] = 1);
})
}
module.exports = {
concat: concat,
uniqueBy: uniqueBy
};
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