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How can I not to return a field from object in JavaScript?


How can I not to return a field from object in JavaScript?

By : user3045247
Date : December 01 2020, 04:52 PM
I wish did fix the issue. The answer depends on the context of your code. If you just want to delete a key-value pair from your object then delete a.randomField will do the trick. You could return a afterwards, but note that this modifies a if it was passed into your function from the outside. In other words:
code :
function foo(x) {
    delete x.randomField;
    return x;
}
a = {
  "data": {
    "foo": {
      "name": "Alex"
    }
  },
  "randomField": {}
}
foo(a)
console.log(a.randomValue) // gives "undefined"
function foo(x) {
    return {data: x.data}
}
b = foo(a)
a.foo.name = "Bob";
console.log(b.foo.name) // Gives "Bob"
function foo(x) {
    y = {}
    Object.keys(x).forEach(function(key) {
        if (key !== "randomField") {
            y[key] = x[key]
        }
    });
    return y;
}


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Javascript: Using object's field's value to determine another object literal's field's name

Javascript: Using object's field's value to determine another object literal's field's name


By : user1637048
Date : March 29 2020, 07:55 AM
will help you I want to use object's field's value while creating another object using literal notation:
code :
var T = {
 fieldName : 'testField'
};
var dummy = T.fieldName;        // dummy variable
var test = {
 dummy : 'value'
};
alert(test.testField);          // test
var T = {
 fieldName : 'testField'
};
// Does work.
var test = {};
test[T.fieldName] = 'value';
alert(test.testField);          // alerts "value"
Javascript function fails to return object when there is a line-break between the return statement and the object?

Javascript function fails to return object when there is a line-break between the return statement and the object?


By : DIPAK PATEL
Date : March 29 2020, 07:55 AM
will help you tl;dr The line break is causing the 'undefined' in the second function. JavaScript doesn't require semicolons in a lot of cases and just assumes them in certain contexts (Automatic Semicolon Insertion).
code :
return (
  ["ul"
  , ["li"
    , ["span", {class: "name"}, this.name]
    , ["span", {id: "x"}, "x"]
    ]
  ]
);
return [
  "ul",
  [
    "li",
    ["span", {class: "name"}, this.name],
    ["span", {id: "x"}, "x"]
  ]
];
function() {
  return (
    doSideEffects(),
    console.log("this is the second side effect"),
    1 + 1
  );
}
I want to return a specific field value from a MongoDB document, but I keep getting [object Promise] as a return value i

I want to return a specific field value from a MongoDB document, but I keep getting [object Promise] as a return value i


By : Steve Sorice
Date : March 29 2020, 07:55 AM
With these it helps This is a problem in the way you are working with promises. Your final console log is outside of the promise chain. Your final console.log actually executes before the database has a chance to query the results. If you wanted the scope to be outside the promise you could return chef after you get your recipe maker
code :
let value_ = getRecipeMaker(req.params.recipeId)
    .then((chef) => {


        // This console.log is printing the value that I want to the 
        // console. So I should get it.
        console.log('chef is ' + chef);
        return chef;


    });
value_.then(chef => {
  console.log(chef);
});
Find id field in array of objects and return another field of that object

Find id field in array of objects and return another field of that object


By : Notice
Date : March 29 2020, 07:55 AM
this will help Just a different variation of the first answer to actually return ONLY the required channel and not all of them.
code :
db.getCollection("collection").aggregate(
    [
        { 
            "$match" : {
                "id" : chatid
            }
        }, 
        { 
            "$unwind" : "$channels"
        }, 
        { 
            "$match" : {
                "channels.id" : channelid
            }
        }, 
        { 
            "$project" : {
                "messages" : {
                    "$slice" : [
                        "$channels.messages", 
                        0.0, 
                        50.0
                    ]
                }
            }
        }
    ]
);
How exactly works the JavaScript object? Can i declare a function as a field of a JavaScript object?

How exactly works the JavaScript object? Can i declare a function as a field of a JavaScript object?


By : DisplayName=
Date : March 29 2020, 07:55 AM
Does that help Functions are first class objects in JavaScript. They can be treated just like any other kind of data.
You can store them in variables, store them in properties, pass them as function arguments, etc.
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