A complete guide to JavaScript typechecking
Learn all you need to know to effectively and efficiently typecheck values in JavaScript.
JavaScript Type Snippets
The JavaScript snippet collection contains a wide variety of ES6 helper functions. It includes helpers for dealing with primitives, arrays and objects, as well as algorithms, DOM manipulation functions and Node.js utilities.
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JavaScript · Boolean traps and how to avoid them
Boolean traps can cause readability and maintainability issues in your code. Learn what they are, how to spot and fix them in this article.
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JavaScript · Where and how can I use the Boolean function in JavaScript?
JavaScript's Boolean function can be used for truth-checking data among other things. Learn how to use it and level up your code today.
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JavaScript · How can I check for a blank value in JavaScript?
JavaScript doesn't have a built-in way to check if a value is blank, but it's easy to create one.
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JavaScript · Typechecking objects with Proxy in JavaScript
Learn how to type check objects at runtime using the powerful Proxy object in JavaScript.
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JavaScript · Check if a JavaScript collection is empty
Quickly determine if a collection of values is empty in JavaScript.
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JavaScript · What is hoisting in JavaScript?
Hoisting comes up a lot during JavaScript interviews. It's a concept that may require some getting used to, so read our guide to learn more.
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JavaScript · What are truthy and falsy values in JavaScript?
JavaScript uses type coercion in Boolean contexts, resulting in truthy or falsy values. Get a hang of how it all works in this quick guide.
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JavaScript · How can I check if a value implements a stream in Node.js?
Learn how to type check for different types of streams in Node.js.
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JavaScript · How can I use optional chaining and nullish coalescing in my JavaScript project?
JavaScript ES2020 introduced optional chaining and nullish coalescing. Learn everything you need to know with this quick guide.
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JavaScript · Typechecking JavaScript arrays with Array.isArray()
Make sure to use the correct method when checking if a JavaScript object is an array.
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JavaScript · Is there a way to use instanceof for primitive JavaScript values?
JavaScript's
instanceofoperator can't be used with primitive values, but there are a some tricks that you can leverage to your advantage. -
JavaScript · Convert a string to a boolean
Have you ever tried to convert the string representation of a boolean to an actual boolean value? Here's a simple way to do it.
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JavaScript · Check if a JavaScript string is a valid JSON
Use a simple JavaScript trick to validate a serialized JSON object.
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JavaScript · What are the differences between var, let and const in JavaScript?
JavaScript variables can be declared a handful of ways. However, understanding their differences can drastically change the way you code.
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JavaScript · Understanding JavaScript variables and scopes
JavaScript developers often get confused by JavaScript's variables and scope. Here's a quick guide to understanding these concepts.
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JavaScript · What's the difference between undeclared, undefined and null in JavaScript?
JavaScript has three different empty states for variables. Learn their differences and how you can check for each one.
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JavaScript · What is the difference between JavaScript's equality operators?
Learn all you need to know about the differences between JavaScript's double equals and triple equals operators.
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JavaScript · What does the double negation operator do in JavaScript?
You've probably come across the double negation operator (
!!) before, but do you know what it does? -
JavaScript · What is the only value not equal to itself in JavaScript?
Did you know there's a JavaScript value that's not equal to itself?
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JavaScript · Are JavaScript strings immutable?
When it comes to immutability, JavaScript strings are often a source of confusion. Yet they're not as complicated as you might expect.
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JavaScript · JavaScript's numeric separators explained
Numeric separators are a somewhat lesser-known JavaScript syntactic sugar that can make working with large constants a lot easier.
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JavaScript · What is the difference between an expression and a statement in JavaScript?
JavaScript distinguishes expressions and statements. Learn their differences in this short article.
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JavaScript · What's the difference between Object.is() and the triple equals operator in JavaScript?
Object.is()and the triple equals operator (===) can both be used for equality checking in JavaScript, but when should you use each one?