'use strict';
-var toLength = require('../internals/to-length');
-var toObject = require('../internals/to-object');
var getBuiltIn = require('../internals/get-built-in');
+var uncurryThis = require('../internals/function-uncurry-this');
+var aCallable = require('../internals/a-callable');
+var lengthOfArrayLike = require('../internals/length-of-array-like');
+var toObject = require('../internals/to-object');
var arraySpeciesCreate = require('../internals/array-species-create');
-var push = [].push;
+var Map = getBuiltIn('Map');
+var MapPrototype = Map.prototype;
+var mapForEach = uncurryThis(MapPrototype.forEach);
+var mapHas = uncurryThis(MapPrototype.has);
+var mapSet = uncurryThis(MapPrototype.set);
+var push = uncurryThis([].push);
// `Array.prototype.uniqueBy` method
// https://github.com/tc39/proposal-array-unique
module.exports = function uniqueBy(resolver) {
var that = toObject(this);
- var length = toLength(that.length);
+ var length = lengthOfArrayLike(that);
var result = arraySpeciesCreate(that, 0);
- var Map = getBuiltIn('Map');
var map = new Map();
- var resolverFunction, index, item, key;
- if (typeof resolver == 'function') resolverFunction = resolver;
- else if (resolver == null) resolverFunction = function (value) {
+ var resolverFunction = resolver != null ? aCallable(resolver) : function (value) {
return value;
};
- else throw new TypeError('Incorrect resolver!');
+ var index, item, key;
for (index = 0; index < length; index++) {
item = that[index];
key = resolverFunction(item);
- if (!map.has(key)) map.set(key, item);
+ if (!mapHas(map, key)) mapSet(map, key, item);
}
- map.forEach(function (value) {
- push.call(result, value);
+ mapForEach(map, function (value) {
+ push(result, value);
});
return result;
};