function where(collection, source) {

var arr = [];

var status = null;

// What's in a name?

for (var i = 0; i < collection.length; i++) {

    for(var imp in source){

        if (source[imp] !== collection[i][imp]) {

            status = 0;

            break;

        }

        status = 1;

    }

    if(status == 1){

        arr.push(collection[i]);

    }

}

return arr;

}

where([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });

function where(collection, source)

{ var arr = [], index = 0; // What's in a name?

// console.log(Object.getOwnPropertyNames(source).length);

//获取对象属性个数

for (; index < collection.length; index++) {

    for (var key in collection[index]) {

        var count = 0;

        for (var key2 in source) {

            if (collection[index].hasOwnProperty(key2)) {

                if (source[key2] == collection[index][key2]) {

                    count++;

                }

                if (count == Object.getOwnPropertyNames(source).length && key == key2) {

                    arr.push(collection[index]);

                }

            }

        }

    }

}

return arr;

}