[nerv_]

Пример: преобразуем строки в числа на всех уровнях

/*
 object-traverse v0.1.0
 [url]https://github.com/nervgh/object-traverse[/url]
*/
!function(a){"use strict";function b(a){return a instanceof Object}function c(a){return"number"==typeof a&&!h(a)}function d(a,c,d,e,f,h){var i=[[],0,g(a).sort(),a],j=[];do{var k=i.pop(),l=i.pop(),m=i.pop(),n=i.pop();for(j.push(k);l[0];){var o=l.shift(),p=k[o],q=n.concat(o),r=c.call(d,k,p,o,q,m);if(r!==!0){if(r===!1){i.length=0;break}if(!(m>=h)&&b(p)){if(-1!==j.indexOf(p)){if(f)continue;throw new Error("Circular reference")}if(!e){i.push(n,m,l,k),i.push(q,m+1,g(p).sort(),p);break}i.unshift(q,m+1,g(p).sort(),p)}}}}while(i[0])}function e(a,b,e,g,h,i){var j=b,k=e,l=1===g,m=!!h,n=c(i)?i:f;d(a,j,k,l,m,n)}var f=100,g=Object.keys,h=a.isNaN;Object.traverse=e}(window);

// ---------------------------

function copy(any) {
    return JSON.parse(JSON.stringify(any));
}

function isString(any) {
    return typeof any === 'string';
}

function isNumberLikeString(string) {
    return /^\d+(.\d+)?$/.test(string);
}

// ---------------------------

var data = {
    delivery: ["7", "24", "35"],
    mode: "0",
    page: "1",
    price: ["0", "33800"]
};

console.log('before', copy(data));

Object.traverse(data, function(node, value, key) {
    if (isString(value) && isNumberLikeString(value)) {
        node[key] = Number(value);
    }
});

console.log('after', copy(data));