partial and findIndex

partial.js

function partial (fn) {
    var initialArgs = Array.prototype.slice.call(arguments, 1);
    return function () {
        var remainingArgs = Array.prototype.slice.call(arguments);
        return fn.apply({}, initialArgs.concat(remainingArgs));
    }
}

function findIndex(arr, predicate) {
    var i;
    for (i = 0; i < arr.length; i += 1) {
        if (predicate(arr[i])) {
            return i;
        }
    }
    return -1;
}


// example use
function compare(id, obj) {
    return id === obj.id;
}

objArr = [
    {name: 'a', id:1},
    {name: 'b', id:2},
    {name: 'c', id:3}
];

alert(findIndex(objArr, partial(compare, 3)));