Sorry for the title but I don't know how to explain it.
The function takes an URI, eg: /foo/bar/1293. The object will, in case it exists, be stored in an object looking like {foo: { bar: { 1293: 'content...' }}}. The function iterates through the directories in the URI and checks that the path isn't undefined and meanwhile builds up a string with the code that later on gets called using eval(). The string containing the code will look something like delete memory["foo"]["bar"]["1293"]
Is there any other way I can accomplish this? Maybe store the saved content in something other than
an ordinary object?
remove : function(uri) {
if(uri == '/') {
this.flush();
return true;
}
else {
var parts = trimSlashes(uri).split('/'),
memRef = memory,
found = true,
evalCode = 'delete memory';
parts.forEach(function(dir, i) {
if( memRef[dir] !== undefined ) {
memRef = memRef[dir];
evalCode += '["'+dir+'"]';
}
else {
found = false;
return false;
}
if(i == (parts.length - 1)) {
try {
eval( evalCode );
} catch(e) {
console.log(e);
found = false;
}
}
});
return found;
}
}
No need for eval here. Just drill down like you are and delete the property at the end:
parts.forEach(function(dir, i) {
if( memRef[dir] !== undefined ) {
if(i == (parts.length - 1)) {
// delete it on the last iteration
delete memRef[dir];
} else {
// drill down
memRef = memRef[dir];
}
} else {
found = false;
return false;
}
});
You just need a helper function which takes a Array and a object and does:
function delete_helper(obj, path) {
for(var i = 0, l=path.length-1; i<l; i++) {
obj = obj[path[i]];
}
delete obj[path.length-1];
}
and instead of building up a code string, append the names to a Array and then call this instead of the eval. This code assumes that the checks to whether the path exists have already been done as they would be in that usage.
Related
I have the following two blocks of code that I am trying to debug.
function getSectionId(target){
let element = target;
if(element.hasAttribute('id')){
console.log(element.id);
return element.id;
}
else {
getSectionId(element.parentElement);
}
};
function coverageLimitHandler(event) {
const target = event.target;
if (target.getAttribute('data-status') !== 'set') {
let itemBlock = addLineItem();
let sectionId = getSectionId(target);
let attribute = '';
console.log(sectionId);
}
}
The event fires and the functions run, but the above gives the unexpected following results
//first-coverage-section (this one is expected.)
//undefined (this is expected to be the same, but is not.)
And I cannot for the life of me figure out why this is happening.
the problem is that your recursive call is not returning anything.
when you do:
getSectionId(element.parentElement);
it will call the function and maybe some day, the if above
if(element.hasAttribute('id')){
console.log(element.id);
return element.id;
}
will return something, but that won't be returned to the previous calls therefore your main call wont have anything to return, so to solve this you need to do this:
function getSectionId(target){
let element = target;
if(element.hasAttribute('id')){
console.log(element.id);
return element.id;
}
else {
// add this return and your function will work correctly.
return getSectionId(element.parentElement);
}
};
basically you have something like this:
function recursiveNotWorking(n) {
if (n === 5) {
return "something"
} else {
// you dont return anything, then something never bubbles up
recursiveNotWorking(n + 1);
}
}
function recursiveWorking(n) {
if (n === 5) {
return "something"
} else {
// we return something
return recursiveWorking(n + 1);
}
}
console.log("NW: ", recursiveNotWorking(1));
console.log("Working: ", recursiveWorking(1));
You need to return the result of the recursive call:
const getSectionId = target => {
if (target.hasAttribute('id') {
return target.id;
}
// You should also check that parentElement exist
// Otherwise you might reach the root node and then parentElement could become null
return getSectionId(target.parentElement);
};
Alos, this can be re-written as well as one liner:
const getSectionId = t => t.id || getSectionId(t.parentElement)
You don't have return in the first function and you don't check on undefined. Also you don't need to use the element variable. It's useless.
Maybe this will work:
function getSectionId(target){
if (typeof target === 'undefined') return null;
if(target.hasAttribute('id')){
console.log(target.id);
return target.id;
}
return getSectionId(target.parentElement);
}
I'm trying to figure out how to check if a deeply nested JSON object, with several unknown arrays and properties contains a property that I'm looking for. I'm looking for a property that is called "isInvalid". If the field is there and the value of that key is true. I want to return false.
var checkValidity = function (data) {
for (var property in data) {
if (data.hasOwnProperty(property)) {
if (property == "isInvalid" && data[property] === true) {
return false;
}
else {
if (typeof data[property] === "object" && data[property] !== null) {
this.checkValidity(data[property]);
}
}
}
}
};
This is the code I've been trying out but I'm unable to get that to work. I have been looking into underscore also, but cant find the needed functions. Anyone has an idea? (No reg exp please)
If you really just want to check for property presence regardless of its particular location within JSON, then the easiest/fastest way is substring search in the source JSON string. If the latter is well-formed, then the property should be encoded in JSON as '"isInvalid":true'.
var checkValidity = function (jsonstr) {
return jsonstr.indexOf('"isInvalid":true') >= 0;
}
You can check like this
var s = {a:'1',b:'2'};
if(Object.getOwnPropertyNames(s).indexOf('a') != -1){
console.log('available');
}else{
console.log('Not available');
};
editing answer... UPDATE
var s = {
a1: '1',
b: '2',
c: {
a: '11'
}
};
var checkValidity = function (data) {
if (Object.getOwnPropertyNames(data).indexOf('a') != - 1) {
console.log('Found that key!!!');
} else {
for (var property in data) {
if (Object.getOwnPropertyNames(property).indexOf('a') != - 1) {
console.log('Found that key!!!');
} else {
if (typeof data[property] === 'object' && data[property] !== null) {
console.log('not found continue in inner obj..');
this.checkValidity(data[property]);
}
}
}
};
};
checkValidity(s);
It tests for every nesting level the property isInvalid and if not, all other properties as object and their content. Array#every breaks if one return is false.
function checkValidity(data) {
return !data.isInvalid && Object.keys(data).every(function (property) {
if (typeof data[property] === "object" && data[property] !== null) {
return checkValidity(data[property]);
}
return true;
});
}
var data = {
a: 1,
b: 2,
c: {
isInvalid: true,
a: false
}
};
document.write('checkValidity() should be false: ' + checkValidity(data) + '<br>');
data.c.isInvalid = false;
document.write('checkValidity() should be true: ' + checkValidity(data));
For complex json searching like this, I would use jsonpath ( http://goessner.net/articles/JsonPath/ ) which is the JSON equivalent of xpath.
To find the isInvalid field no matter where it is in the json, you would use it like this:
jsonPath(data, "$..isInvalid")
Let's say we have this JavaScript object:
var object = {
innerObject:{
deepObject:{
value:'Here am I'
}
}
};
How can we check if value property exists?
I can see only two ways:
First one:
if(object && object.innerObject && object.innerObject.deepObject && object.innerObject.deepObject.value) {
console.log('We found it!');
}
Second one:
if(object.hasOwnProperty('innerObject') && object.innerObject.hasOwnProperty('deepObject') && object.innerObject.deepObject.hasOwnProperty('value')) {
console.log('We found it too!');
}
But is there a way to do a deep check? Let's say, something like:
object['innerObject.deepObject.value']
or
object.hasOwnProperty('innerObject.deepObject.value')
There isn't a built-in way for this kind of check, but you can implement it easily. Create a function, pass a string representing the property path, split the path by ., and iterate over this path:
Object.prototype.hasOwnNestedProperty = function(propertyPath) {
if (!propertyPath)
return false;
var properties = propertyPath.split('.');
var obj = this;
for (var i = 0; i < properties.length; i++) {
var prop = properties[i];
if (!obj || !obj.hasOwnProperty(prop)) {
return false;
} else {
obj = obj[prop];
}
}
return true;
};
// Usage:
var obj = {
innerObject: {
deepObject: {
value: 'Here am I'
}
}
}
console.log(obj.hasOwnNestedProperty('innerObject.deepObject.value'));
You could make a recursive method to do this.
The method would iterate (recursively) on all 'object' properties of the object you pass in and return true as soon as it finds one that contains the property you pass in. If no object contains such property, it returns false.
var obj = {
innerObject: {
deepObject: {
value: 'Here am I'
}
}
};
function hasOwnDeepProperty(obj, prop) {
if (typeof obj === 'object' && obj !== null) { // only performs property checks on objects (taking care of the corner case for null as well)
if (obj.hasOwnProperty(prop)) { // if this object already contains the property, we are done
return true;
}
for (var p in obj) { // otherwise iterate on all the properties of this object.
if (obj.hasOwnProperty(p) && // and as soon as you find the property you are looking for, return true
hasOwnDeepProperty(obj[p], prop)) {
return true;
}
}
}
return false;
}
console.log(hasOwnDeepProperty(obj, 'value')); // true
console.log(hasOwnDeepProperty(obj, 'another')); // false
Alternative recursive function:
Loops over all object keys. For any key it checks if it is an object, and if so, calls itself recursively.
Otherwise, it returns an array with true, false, false for any key with the name propName.
The .reduce then rolls up the array through an or statement.
function deepCheck(obj,propName) {
if obj.hasOwnProperty(propName) { // Performance improvement (thanks to #nem's solution)
return true;
}
return Object.keys(obj) // Turns keys of object into array of strings
.map(prop => { // Loop over the array
if (typeof obj[prop] == 'object') { // If property is object,
return deepCheck(obj[prop],propName); // call recursively
} else {
return (prop == propName); // Return true or false
}
}) // The result is an array like [false, false, true, false]
.reduce(function(previousValue, currentValue, index, array) {
return previousValue || currentValue;
} // Do an 'or', or comparison of everything in the array.
// It returns true if at least one value is true.
)
}
deepCheck(object,'value'); // === true
PS: nem035's answer showed how it could be more performant: his solution breaks off at the first found 'value.'
My approach would be using try/catch blocks. Because I don't like to pass deep property paths in strings. I'm a lazy guy who likes autocompletion :)
JavaScript objects are evaluated on runtime. So if you return your object statement in a callback function, that statement is not going to be evaluated until callback function is invoked.
So this function just wraps the callback function inside a try catch statement. If it catches the exception returns false.
var obj = {
innerObject: {
deepObject: {
value: 'Here am I'
}
}
};
const validate = (cb) => {
try {
return cb();
} catch (e) {
return false;
}
}
if (validate(() => obj.innerObject.deepObject.value)) {
// Is going to work
}
if (validate(() => obj.x.y.z)) {
// Is not going to work
}
When it comes to performance, it's hard to say which approach is better.
On my tests if the object properties exist and the statement is successful I noticed using try/catch can be 2x 3x times faster than splitting string to keys and checking if keys exist in the object.
But if the property doesn't exist at some point, prototype approach returns the result almost 7x times faster.
See the test yourself: https://jsfiddle.net/yatki/382qoy13/2/
You can also check the library I wrote here: https://github.com/yatki/try-to-validate
I use try-catch:
var object = {
innerObject:{
deepObject:{
value:'Here am I'
}
}
};
var object2 = {
a: 10
}
let exist = false, exist2 = false;
try {
exist = !!object.innerObject.deepObject.value
exist2 = !!object2.innerObject.deepObject.value
}
catch(e) {
}
console.log(exist);
console.log(exist2);
Try this nice and easy solution:
public hasOwnDeepProperty(obj, path)
{
for (var i = 0, path = path.split('.'), len = path.length; i < len; i++)
{
obj = obj[path[i]];
if (!obj) return false;
};
return true;
}
In case you are writing JavaScript for Node.js, then there is an assert module with a 'deepEqual' method:
const assert = require('assert');
assert.deepEqual(testedObject, {
innerObject:{
deepObject:{
value:'Here am I'
}
}
});
I have created a very simple function for this using the recursive and happy flow coding strategy. It is also nice to add it to the Object.prototype (with enumerate:false!!) in order to have it available for all objects.
function objectHasOwnNestedProperty(obj, keys)
{
if (!obj || typeof obj !== 'object')
{
return false;
}
if(typeof keys === 'string')
{
keys = keys.split('.');
}
if(!Array.isArray(keys))
{
return false;
}
if(keys.length == 0)
{
return Object.keys(obj).length > 0;
}
var first_key = keys.shift();
if(!obj.hasOwnProperty(first_key))
{
return false;
}
if(keys.length == 0)
{
return true;
}
return objectHasOwnNestedProperty(obj[first_key],keys);
}
Object.defineProperty(Object.prototype, 'hasOwnNestedProperty',
{
value: function () { return objectHasOwnNestedProperty(this, ...arguments); },
enumerable: false
});
I am using custom javascript functions provided at this link (http://km0.la/js/mozXPath/) to implement particular XML functionality in FireFox.
Here is the code:
// mozXPath
// Code licensed under Creative Commons Attribution-ShareAlike License
// http://creativecommons.org/licenses/by-sa/2.5/
if( document.implementation.hasFeature("XPath", "3.0") ) {
if( typeof XMLDocument == "undefined" ) { XMLDocument = Document; }
XMLDocument.prototype.selectNodes = function(cXPathString, xNode) {
if( !xNode ) { xNode = this; }
var oNSResolver = this.createNSResolver(this.documentElement);
var aItems = this.evaluate(cXPathString, xNode, oNSResolver,
XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
var aResult = [];
for( var i = 0; i < aItems.snapshotLength; i++) {
aResult[i] = aItems.snapshotItem(i);
}
return aResult;
}
XMLDocument.prototype.selectSingleNode = function(cXPathString, xNode) {
if( !xNode ) { xNode = this; }
var xItems = this.selectNodes(cXPathString, xNode);
if( xItems.length > 0 ){ return xItems[0]; }
else{ return null; }
}
Element.prototype.selectNodes = function(cXPathString) {
if(this.ownerDocument.selectNodes) {
return this.ownerDocument.selectNodes(cXPathString, this);
}
else { throw "For XML Elements Only"; }
}
Element.prototype.selectSingleNode = function(cXPathString) {
if(this.ownerDocument.selectSingleNode) {
return this.ownerDocument.selectSingleNode(cXPathString, this);
}
else { throw "For XML Elements Only"; }
}
}
Assuming the XML object has been defined and loaded with XML content, here is an example of how one would access a an XML tag named "cd_rank":
var cd_rank_XMLObj = XMLObj.selectSingleNode("cd_rank");
What I want to do is add the property "nodeTypedValue" to the selectSingleNode() function, but I'm not sure how to do this. In the Element.prototype.selectSingleNode function, I tried adding:
this.prototype.nodeTypedValue = this.textContent;
However, it's giving me an error saying it's undefined. I even tried adding it outside of the function, just to dumb it down and get the concept, and it also says it's undefined:
var XMLObj.selectSingleNode.prototype.nodeTypedValue = XMLObj.textContent;
alert(XMLObj.selectSingleNode("cd_rank").nodeTypedValue);
Essentially what I'm trying to do, I suppose, is add a prototype property to a prototype function. But I need some help with this. How can i add "nodeTypedValue" such that I write "XMLObj.selectSingleNode(Path).nodeTypedValue"?
Okay, I think I figured out how to add it inside the function, probably due more to luck than logic:
Element.prototype.selectSingleNode = function(cXPathString){
if(this.ownerDocument.selectSingleNode) {
var result = this.ownerDocument.selectSingleNode(cXPathString, this);
if (result != null) {
result.nodeTypedValue = result.textContent;
}
return result;
}
else{throw "For XML Elements Only";}
}
Looking for another eye on making the following Javascript more efficient.
The following JSON is produced from a Resteasy service:
var testing = {
"com:klistret:cmdb:ci:pojo:successful":true,
"com:klistret:cmdb:ci:pojo:count":1,
"com:klistret:cmdb:ci:pojo:elements":{
"com:klistret:cmdb:ci:pojo:id":123,
"com:klistret:cmdb:ci:pojo:name":"Mars",
"com:klistret:cmdb:ci:pojo:type":{
"com:klistret:cmdb:ci:pojo:id":1,
"com:klistret:cmdb:ci:pojo:name":"Environment"
},
"com:klistret:cmdb:ci:pojo:configuration":{
"#www:w3:org:2001:XMLSchemainstance:type":"Environment",
"#Watermark":"past",
"com:klistret:cmdb:ci:commons:Name":"Mars"
}
}
};
Extended the Extjs JSONReader to handle key depths higher than 2 in the createAccessor method. Wondering if there is a way to make the code more efficient? The function below will be called like function(testing, "com:klistret:cmdb:ci:pojo:configuration.#Watermark") where the com:klistret:cmdb:ci:pojo:elements property is the root.
createAccessor : function(){
var re = /[\[\.]/;
return function(expr) {
if(Ext.isEmpty(expr)){
return Ext.emptyFn;
}
if(Ext.isFunction(expr)){
return expr;
}
# THIS FUNCTION I WANT TO BE EFFICIENT
return function(obj){
while (String(expr).search(re) !== -1) {
var i = String(expr).search(re);
var key = expr.substring(0, i);
if (obj.hasOwnProperty(key)) {
obj = obj[key];
}
expr = expr.substring(i+1, expr.length);
}
return obj[expr];
};
};
}()
This is what I use. I only allow dot annotation, mind:
Ext.override(Ext.data.JsonReader, {
createAccessor: function() {
return function(expr) {
if (Ext.isEmpty(expr)) {
return Ext.emptyFn;
} else if (Ext.isFunction(expr)) {
return expr;
} else {
return function(obj) {
var parts = (expr || '').split('.'),
result = obj,
part,
match;
while (parts.length > 0 && result) {
part = parts.shift();
match = part.match(/^(.+?)(\[(\d+)\])?$/);
result = result[match[1]];
if (result && match[3]) {
result = result[match[3]];
}
}
return result;
}
}
};
}()
});
A basic optimization would be to avoid scanning the string twice with search, which is pretty slow.
The best you could do is replace all the string scanning and substring extraction with a single call to expr.split('.'), which would support accessors of the form aaa.bbb.ccc.ddd and turn them into an array like ['aaa','bbb','ccc','ddd']. The other two characters you seem to support ([ and ]) wouldn't work.
Alternately, you could do an initial match for /[^\].[]+/g over your entire string and keep the matches to obtain a similar array, but this would possibly be slower than the previous solution.