javascript - 某元素在不在数组里边

Answer 1

用indexOf不合适， 因为你的数组里都是对象，所以还是这样吧：

var obj = [{
    'code': '57442329a3413100625f194f',
    'poll': 7
}, {
    'code': '574417bc79df540065d92df7',
    'poll': 18
}, {
    'code': '574a841d1532bc006068c6c9',
    'poll': 5
}, {
    'code': '574a97fe2b51e90056e423c0',
    'poll': 12
}];

var isIn = function(code, items) {
    return !!items.filter(function(item) {
            return item.code === code;
        }).length;
};


console.log(isIn('574417bc79df540065d92df7', obj));//true
console.log(isIn('asdf', obj));//false