I have an object and I want to copy this object and remove every instance of description from it. What is an elegant way of doing this?
here's how the object looks:
{
properties: {
a: {
value: foo,
description: bar
},
b: {
value: foo,
description: bar
}
}
Use the second argument to JSON.parse:
const output = JSON.parse(
JSON.stringify(input),
(key, value) => key === "description" ? undefined : value
);
A return value of undefined from this function tells JSON.parse to skip it.
Related
I am practicing JavaScript Proxies and want to access a method from another object but with an empty Proxy object:
const data = {
hello: {
log() {
return 'hello log'
},
},
hi: {
log() {
return 'hi log'
},
},
}
const blankObject = {} // I can just pass the data object but I want an empty one
const proxy = new Proxy(blankObject, {
get(target, key) {
const v = target[key]
if (typeof v === 'function') {
// if data.hello.log() or data.hi.log()
return function() {
return data[key]['WHAT_TO_DO']// access data.hello.log or data.hi.log() here?
}
}
return v
}
})
proxy.hello.log() // hello log;
Basically I'm trying to check if that method property exist in another object. I just want to tell the proxy to get the value from another object without passing it into the constructor.
I don't understand why you want to use a different object than the object you are proxying. It makes little sense to proxy an empty object instead.
Secondly, if you are going to access the hello property of the proxy object, then realise that this hello value -- as found in the data object -- is not proxied, so it is not in this proxy that you should check whether the property is a function. At this point the log property is not accessed yet. It's only about the hello access that the proxy is aware.
But you can divert the path to the data object when hello is accessed, by verifying it is indeed a property of the data object. So:
const data = {
hello: {
log() {
return 'hello log';
},
},
hi: {
log() {
return 'hi log'
},
},
}
const blankObject = {};
const proxy = new Proxy(blankObject, {
get(target, key) {
if (key in data) return data[key]; // <---
return target[key]; // default
}
});
console.log(proxy.hello.log()); // hello log;
still trying to figure out what in the world you are trying to accomplish here. you're trying to add a method from one object, to another object?
const blankObject = { hello: data.hello };
though this feels a bit hacky. would probably be best to just pass the whole data object into the constructor, so that the blank object has a reference to it, and can use its methods whenever it needs to.
Doesn't matters, using a test, no needs to over-engineer!
let data = {
hello: {
log() {
return 'hello log'
},
},
hi: {
log() {
return 'hi log'
},
},
}
let blankObject = {} // I can just pass the data object but I want an empty one
// We test if the object has a given property and return accordingly
console.log(
(blankObject["hello"]) ? blankObject.hello.log() : data.hello.log()
)
I need to check key exist in object of object. I have array of object and in every object i have one other object. I need to check the key is existing in object of object
var myarr = [{
hello: "world",
payload: {
kekek: 'sdfsdfsdf',
baby: 'sdfsdfsdfds'
}
},
{
hello: "world",
payload: {
qwe: 'sdfsdfsdf',
baby: 'sdfsdfsdfds'
}
}, {
hello: "world",
payload: {
qwe: 'sdfsdfsdf',
baby: 'sdfsdfsdfds'
}
},
{
hello: "world",
payload: {
asdf: 'sdfsdfsdf',
baby: 'sdfsdfsdfds'
}
}
]
let pp = myarr.payload.hasOwnProperty('eekey')
console.log(pp).
I need to check kekek in payload.
If I understood correctly, you want to check if every of object of your array contains a specific key in payload property. If so, you can use in operator to check if a property is present in a object. You can improve this snippet by checking if value is defined.
let key = 'kekek';
const everyObjectHasKey = myarr.every(item => item.payload && key in item.payload);
console.log(everyObjectHasKey);
In this link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every , you can see more about every method for arrays
My object
object1 ={
name: xxx,
Id: 212
}
I need a output like:
{
212:xxx
}
Can anyone help me to do it?
for(var key in object1) {
if(object1.hasOwnProperty(key))
{
console.log( eachPeriod[key]);
}
}
You can set the key of the object with a variable enclosed with brackets as [Id]. The convert() function takes the object as an argument and assigns the value of name and Id to the corresponding variables by destructuring. Then, use those variables to construct the object.
const obj = {
name: 'xxx',
Id: 212
};
function convert ({ name, Id }) {
return {
[Id]: name
};
}
console.log(convert(obj));
Is possible dynamically add properties to nested object in Typescript ? Because my object is dynamic. In one case i have obj.
[
{someObject},
{
prop1:1,
columns: [
components: [
columns: [
components:[
{
type: number,
key: 'key1'
},
{
type: textfield,
key: 'key2'
}
]
]
]
]
}
]
And for example for object with key key2 i need add some flag. And in another case i get object less nested. Does exists any for example lodash function for this operation, or i have to iterate this object by recursion ?
You will have to recursively search. Thankfully this is not too difficult to implement:
const findAndUpdate = ($obj, $key, $val) => {
Object.keys($obj).includes($key) ?
$obj[$key] = $val
: Object.values($obj).forEach($nestedObj => findAndUpdate($nestedObj, $key, $val));
return $obj;
}
I used Object.<method> instead of lodash methods so that this can be easily replicated accross enviroments. This function will take in an initial object, the key you want to update and the value that you want to update it to.
Usage:
const foo = {
b: {
c: {
d: 5
}
}
}
findAndUpdate(foo, "d", 56);
console.log(foo) // -> { b: { c: { d: 56 } } } }
It checks if the key exists in the current layer of the object. If it doesn't then we call the function again for each object in the current layer - passing in the original object as a reference. If it does find a key in the current layer, then it will update the object that the reference points to. Eventually after the stack is cleared then we return our original updated object. Obviously if no keys are found that match the target key originally passed in then the object will remain unchanged.
If you want more customisation you could change the $val to take in a function $func instead:
const findAndUpdate = ($obj, $key, $func) => {
Object.keys($obj).includes($key) ?
$obj[$key] = $func($obj[$key])
: Object.values($obj).forEach($nestedObj => findAndUpdate($nestedObj, $key, $val));
return $obj;
}
Then you can now do something like this:
findAndUpdate(foo, "d", old => old+1 );
console.log(foo) // -> { b: { c: { d: 6 } } } }
I have the following object names $scope.parameters. When i execute console.log as shown below, i get this result
console.log($scope.parameters);
Result
Object { Name: "Diana", id: 234, Size: Object, Location: Object, Details: "none" }
Name: "Diana"
id: 234,
Size: Object
Location: Object
Details: "none"
As the result shows the elements Size and Location as Object, i want it to be replaced with null. Also, i want it to be dynamic. for e.g. if any of the above elements are Object, it should replace it to null automatically.
Can someone please let me know how to achieve this.
Test out each key of the object with its type if object make them null
if (Object.getPrototypeOf($scope.parameters.Size) === Object.prototype) {
// True if its object change it to null
$scope.parameters.Size = null;
} else {
// do nothing
}
Make a function which takes parameters to test it out and return.
angular.forEach($scope.parameters, function(value, key) {
if(typeof value === "object"){
console.log(key);
$scope.parameters[key] = null;
}
});