Why is this undefined in a function?

A function is said to be “undefined” at points outside of its domain – for example, the real-valued function. is undefined for negative. (i.e., it assigns no value to negative arguments). In algebra, some arithmetic operations may not assign a meaning to certain values of its operands (e.g., division by zero).

How do you know if undefined?

If it is undefined, it will not be equal to a string that contains the characters “undefined”, as the string is not undefined. You can check the type of the variable: if (typeof(something) != “undefined”) …

Why do I get undefined in console?

The result of evaluating console. log() is undefined since console. log does not explicitly return something. It has the side effect of printing to the console.,A variable declaration does not produce a value so again undefined is printed to the console.

Why does JavaScript show undefined?

JavaScript assigns ‘undefined’ to any object that has been declared but not initialized or defined. In other words, in a case where no value has been explicitly assigned to the variable, JavaScript calls it ‘undefined’. 2. Array index or object property that does not exist.

Why this keyword is undefined in event handler?

The keyword this changes what it refers to based upon the current “operational context” the JavaScript runtime is executing. That means that when an event occurs, the event hander is operating in the context of that event – so this refers to the Event Object and not the object that happens to contain the event handler.

What makes something undefined?

How do we know when a numerical expression is undefined? It is when the denominator equals zero. When we have a denominator that equals zero, we end up with division by zero. We can’t divide by zero in math, so we end up with an expression that we can’t solve.

What does it mean if something is undefined?

without fixed limits; indefinite in form, extent, or application: undefined authority; undefined feelings of sadness. not given meaning or significance, as by a definition; not defined or explained: an undefined term.

Is undefined true or false JavaScript?

The Boolean value of undefined is false. The value of Not only undefined but also null, false, NaN, empty string is also false.

Is null == undefined?

It means null is equal to undefined but not identical. When we define a variable to undefined then we are trying to convey that the variable does not exist . When we define a variable to null then we are trying to convey that the variable is empty. understanding.

Why this is undefined TypeScript?

The Undefined means a variable has been declared but has not yet been assigned a value. The undefined variables do not have any value. It is an unintentional absence of any value. Whenever we declare a variable without initializing it with a value, TypeScript initializes it as undefined .

Is undefined === null?

null is a special value meaning “no value”. null is a special object because typeof null returns ‘object’. On the other hand, undefined means that the variable has not been declared, or has not been given a value.

Why is the result of a function undefined in Python?

The result is undefined because declarations/definition of var text within the function is after printing it out to console . And as you are declaring variable within the function ,its scope is within the function , though you have declared var text outside the function (global scope) .

Why is the result of a nested promise undefined?

No return value makes the resolved value be undefined. Your last .then is receiving the result created in your nested Promise, and, since you are not returning anything ( i.e. you are just doing console.log (‘hello’) ) then result is undefined. You can see this behaviour if you actually return something :

Why is the result of function logit() undefined?

If you are thinking when you execute this piece of code why “the result of function logIt ()” undefined, simply because logIt () doesn’t return anything. Put a return statement and result will be that value. The result is undefined because declarations/definition of var text within the function is after printing it out to console .

Why does my then() method return undefined in JavaScript?

Because you’ve chained several promises together and one of your .then () handlers returns nothing. returns nothing which is essentially the same as return undefined and therefore the resolved value of the chain becomes undefined. Remember that the return value of every .then () handler becomes the resolved value of the chain going forward.