Quick Answer: Javascript “” Ou ”?

What does || mean in JS?

The Logical OR operator ( || ) is an operator that returns its first or second operand depending on whether the first is truthy. A “truthy” value means anything other than 0, undefined, null, “”, or false.

What is << in JavaScript?

The left shift operator ( << ) shifts the first operand the specified number of bits to the left. Excess bits shifted off to the left are discarded. Zero bits are shifted in from the right.

What is comparison operator in JavaScript?

A comparison operator compares its operands and returns a logical value based on whether the comparison is true. The operands can be numerical, string, logical, or object values. Strings are compared based on standard lexicographical ordering, using Unicode values.

What is a JavaScript expression?

An expression is any valid set of literals, variables, operators, and expressions that evaluates to a single value. The value may be a number, a string, or a logical value. Conceptually, there are two types of expressions: those that assign a value to a variable, and those that simply have a value.

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What is the three dots in JavaScript?

The three dots in JavaScript are the spread / rest operator. The spread syntax allows an expression to be expanded in places where multiple arguments are expected. The rest parameter syntax is used for functions with a variable number of arguments. The spread / rest operator for arrays was introduced in ES6.

What’s JavaScript used for?

JavaScript is a text-based programming language used both on the client-side and server-side that allows you to make web pages interactive. Where HTML and CSS are languages that give structure and style to web pages, JavaScript gives web pages interactive elements that engage a user.

Is JavaScript a 32-bit?

JavaScript has several bitwise operators that work with 32-bit integers. That is, they convert their operands to 32-bit integers and produce a result that is a 32-bit integer. Use cases for these operators include processing binary protocols, special algorithms, etc.

Should you use strict mode JavaScript?

Strict mode is an important part of modern JavaScript. Strict mode makes several changes to JavaScript semantics. It eliminates silent errors and instead throws them so that the code won’t run with errors in the code. It will also point out mistakes that prevent JavaScript engines from doing optimizations.

What does shift do in JavaScript?

The shift() method removes the first element from an array and returns that removed element. This method changes the length of the array.

Where should JavaScript be placed?

JavaScript in body or head: Scripts can be placed inside the body or the head section of an HTML page or inside both head and body. JavaScript in head: A JavaScript function is placed inside the head section of an HTML page and the function is invoked when a button is clicked.

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Is a number JavaScript?

In JavaScript, there are two ways to check if a variable is a number: isNaN() – Stands for “is Not a Number”, if variable is not a number, it return true, else return false. typeof – If variable is a number, it will returns a string named “number”.

Is JavaScript an operator?

An operator is capable of manipulating a certain value or operand. Operators are used to perform specific mathematical and logical computations on operands. In other words, we can say that an operator operates the operands. In JavaScript operators are used for compare values, perform arithmetic operations etc.

Does JavaScript ignore multiple spaces?

JavaScript ignores multiple spaces. You can add white space to your script to make it more readable.

What is the difference between statement and expression JavaScript?

If the browser returns undefined after each line of execution, its a statement. If the browser returns any value other than undefined after each line of execution, its an expression.

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