RequestAnimationFrame would be true and one more ! So if requestAnimationFrame was assigned a function then ! RequestAnimationFrame would be false and one more ! Their intention is to set rafSupported to true or false based on the availability of function in requestAnimationFrame. If that element does in fact exist, the expression will evaluate as true, and the code block will be executed.

Its meaning depends on what a project’s maintainers assign javascript breakout to it and is usually used to differentiate a particular group of variables from the rest. The dollar sign is treated just like a normal letter or underscore (_). It has no special significance to the interpreter. Functionally, it looks like it allows you to nest a variable inside a string without doing concatenation using the + operator. I’m looking for documentation on this feature. If requestAnimationFrame was assigned undefined then !

• So if requestAnimationFrame was assigned a function then !
• Others have written about the touch eventsin much more detail.
• object Object is the default toString representation of an object in javascript.
• If requestAnimationFrame was assigned undefined then !

Note that there are some unintuitive cases where a Boolean will be cast to a number (true is cast to 1 and false to 0) when comparing a Boolean to a number. Though, again, these are cases where you’re comparing a non-Boolean to a hard-typed Boolean, which is, in my opinion, a serious mistake. Foo applies the unary not operator twice and is used to cast to a Boolean type similar to the use of unary plus +foo to cast to a number and concatenating an empty string  »+foo to cast to a string. What we wish to determine in the comparison is the « truth » about the value of a reference, not the value of the reference itself. There is a use-case where we might want to know the truth about a value, even if we expect the value to be false (or falsey), or if we expect the value not to be typeof boolean.

Old answer

• It always takes the sign of the dividend, not the divisor.
• I can see why everyone builds native apps for mobile!
• Because document.getElementById() is a « truthy » expression that will evaluate as true in this if() statement, but it is not an actual Boolean value of true.
• I’ve even written a book and cowritten another one.

(unless there’s a good reason not to). I think this is a good answer b/c it avoids lots of indentation and b/c the OP specifically asked for a solution that doesn’t throw.

JS String Methods

If myObject was an any, you’re back in JavaScript’s Wild West and can return it without !! Was enough to cast to a Boolean, and you’re just checking equality. Operator was included in ES2020, which is supported by Node 14 (released in April 2020). Related to Is there a « null coalescing » operator in JavaScript? Operator which I see in use more frequently.

uses the right value if left is falsy, while the nullish coalescing operator ??

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If you can’t use every() or slice(), you can check a shouldSkip flag at the start of your forEach() callback. If youset shouldSkip to true, the forEach() callback returns immediately. This tells the function to sort uppercase values before lowercase values. The second parameter in the localeCompare function is to define the locale but if you leave it as undefined it automatically figures out the locale for you. If you want to sort ascending switch the expressions on each side of the minus sign.

Syntax

(Think poor man’s way of « type-casting ».) Its intent is usually to convey to the reader that the code does not care what value is in the variable, but what its « truth » value is. To put it simply, you should likely use the nullish coalescing operator ?? It will be less cognitive load to figure out whether it’s a potential bug or not. There is also not much reason to avoid it. It’s newer than the boolean OR, so it doesn’t work on older environments, that’s true, however nowadays you should likely be transpiling your code for those.

Breakout game in JavaScript

Of course, you can specify a different return value. Whatever value is returned will be logged to the console using the above example. You can apply this principle over and over, at all levels of your code. I’m a Microsoft MVP, a software architect and a polyglot developer. I’m into mobile apps and development process optimization. I love teaching and helping others, therefore I blog, write articles, and speak at local events.

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Uses the right value if left is null or undefined. The every() function behaves exactly like forEach(), except it stops iterating through the array whenever the callback function returnsa falsy value. Template literals were introduced in ECMAScript 6 (ES2015) and provide a more modern and convenient way to work with strings in JavaScript. They are enclosed by backticks (“`) instead of single or double quotes, and allow for embedded expressions, multiline strings, and more. For sorting a array you must define a comparator function.

This tutorial series shows how to create a simple platform game using Phaser, covering fundamentals such as sprites, collisions, physics, collectables, and more. In this step-by-step tutorial you’ll implement the same breakout clone as the previous tutorial series, except that this time you’ll do it using the Phaser HTML game framework. This idea here is to teach some of the fundamentals (and advantages) of working with frameworks, along with fundamental game mechanics. This page contains multiple tutorial series that highlight different workflows for effectively creating different types of web games. In this switch statement example, the break statement is used to terminate the switch statement so that once a match is found no further values are not evaluated.

The special « array » arguments is available inside the function; it contains all the arguments, starting from index 0 to N – 1 (where N is the number of arguments passed). It’s pretty common to see JavaScript libraries to do a bunch of checks on optional inputs before the function actually starts. Object objects, unlike Arrays and other classes are treated simply as associative arrays (sometimes considered ordered, and sometimes considered unordered). To demonstrate this further consider the following example in which we are adding a new property to String constructor prototype.