var patch = jdp.patch = function()

in pytheas-core/src/main/resources/js/jsondiffpatch.js [442:544]
92 lines of code
28 McCabe index (conditional complexity)

    var patch = jdp.patch = function(o, pname, d, path) {
    
        var p, nvalue, subpath = '', target;
        
        if (typeof pname != 'string') {
            path = d;
            d = pname;
            pname = null;
        }
        else {
            if (typeof o != 'object') {
                pname = null;
            }
        }
        
        if (path) {
            subpath += path;
        }
        subpath += '/';
        if (pname !== null) {
            subpath += pname;
        }
        
        
        if (typeof d == 'object') {
            if (isArray(d)) {
                // changed value
                if (d.length < 3) {
                    nvalue = d[d.length - 1];
                    if (pname !== null) {
                        objectSet(o, pname, nvalue);
                    }
                    return nvalue;
                }
                else {
                    if (d[2] == 0) {
                        // undefined, delete value
                        if (pname !== null) {
                            objectSet(o, pname);
                        }
                        else {
                            return;
                        }
                    }
                    else 
                        if (d[2] == 2) {
                            // text diff
                            if (!jdp.config.textPatch) {
                                diff_match_patch_autoconfig();
                            }
                            if (!jdp.config.textPatch) {
                                throw new Error("textPatch function not found");
                            }
                            try {
                                nvalue = jdp.config.textPatch(objectGet(o, pname), d[0]);
                            } 
                            catch (text_patch_err) {
                                throw new Error('cannot apply patch at "' + subpath + '": ' + text_patch_err);
                            }
                            if (pname !== null) {
                                objectSet(o, pname, nvalue);
                            }
                            return nvalue;
                        }
                        else {
                            throw new Error("invalid diff type");
                        }
                }
            }
            else {
                if (d._t == 'a') {
                    // array diff
                    target = pname === null ? o : objectGet(o, pname);
                    if (typeof target != 'object' || !isArray(target)) {
                        throw new Error('cannot apply patch at "' + subpath + '": array expected');
                    }
                    else {
                        for (p in d) {
                            if (p !== '_t' && d.hasOwnProperty(p)) {
                                patch(target, p, d[p], subpath);
                            }
                        }
                    }
                }
                else {
                    // object diff
                    target = pname === null ? o : objectGet(o, pname);
                    if (typeof target != 'object' || isArray(target)) {
                        throw new Error('cannot apply patch at "' + subpath + '": object expected');
                    }
                    else {
                        for (p in d) {
                            if (d.hasOwnProperty(p)) {
                                patch(target, p, d[p], subpath);
                            }
                        }
                    }
                }
            }
        }
        
        return o;
    }