ES5 ES6中Array对象去除重复项的方法总结

[false, true, undefined, null, NaN, 0, 1, {}, {}, 'a', 'a', NaN].uniq()

[false, true, undefined, null, NaN, 0, 1, {}, {}, 'a']

Array.prototype.uniq = function () {
 var arr = [];
 var flag = true;
 this.forEach(function(item) {
 // 排除 NaN (重要！！！)
 if (item != item) {
 flag && arr.indexOf(item) === -1 ? arr.push(item) : '';
 flag = false;
 } else {
 arr.indexOf(item) === -1 ? arr.push(item) : ''
 }
 });
 return arr;
}

[false, true, undefined, null, NaN, 0, 1, {}, {}, 'a', 'a', NaN].uniq()

[false, true, undefined, null, NaN, 0, 1, {}, {}, 'a']

Array.prototype.uniq = function() {
 return Array.from(new Set(this));
}

Array.prototype.uniq = function() {
 return [...new Set(this)];
}