Hire fast with Proxify
Elman H. Germany
7 years experience
- HTML / CSS
Oleksandra H. France
5 years experience
Trusted member since 2019
Zlatko J. Serbia
10 years experience
It was previously known as LiveScript and released in 1995.
Some steps aren't only preferable but essential. Here are a few.
Technical skills checklist
Basic algorithms and data structures
Web development tools (NPM, Git, or Webpack)
Analyzing system risks and requirements
Asynchronous programming (Prototypes, Hosting, Scope, Coercion, etc.)
Checklist of preferred qualifications
To find those diamonds in the rough in hundreds of candidates, you can shortlist the ones who also have:
A degree in Computer Science or a related field
Knowledge of ES6 language features (e.g., ECMAScript 6)
Interview questions and answers
1. Can you define isNaN and its usage?
Example answer: NaN means "not a number," and isNaN lets us know which value is, in fact, NaN. When we use the function isNaN(), we try to discover if a value has an incorrect or illegal number. If this function returns as 'true' the examined value is NaN.
2. Can you define "negative infinity"?
3. Could you explain the "global variables "?
Example answer: Global variables can be accessed from anywhere in the program. Global variables are always declared via a window object or outside a function. We can access them from any other function. An example of a global variable is var.
Example answer: The SessionState is data that persists in a specific server. When we close the browser, or a session expires, this data availability also stops. We can access this precise data from all web app pages.
The ViewState is a group of controls' values on a page and the client browser. ViewState stores information only on the client's side.
The SessionState is saved on a server, but the ViewState is saved on the page itself, and we can see it from just a single page, not more.
Example answer: We use these looping structures when we work on repetitive tasks, i.e., this feature helps us to repeat functions. The loops don't stop running unless their condition appears "false.”
Example answer: "null' means either no object or no value. The other name for this is null string, which intentionally has no value. We call this a primitive value because it has no array object.
For context, the primitive values can be divided into:
7. Can you explain how to use 'Void(0)'?
8. Can you explain more about the 'pop()' method?
Example answer: We use this method when we need to remove the last array element, i.e., pop() helps us retrieve that same element once someone removes it. This way, we adjust the array length accordingly with the help of the syntax array.pop()
9. Can you differentiate between .call() and .apply()?
Example answer: These two are similar to one another. If we know some function's arguments and the function number, we use .call() as a predefined method. With this method, a specific object can take on another method from a different object.
On the other hand, we use .apply() if we don't know the function number, but we can write a method we can later use on more different objects.
Example answer: We use these functions to create anonymous expressions or write expressions for anonymous functions. Such functions don't support the keywords new target, arguments, super, or this.
We use arrow functions when passing a function like a parameter for another demanding function.
Example answer: There are six such types, divided into three categories:
- Primary (primitive) – Boolean, String, and Number
- Composite (or reference) – Object, Function, and Array
- Special – Null and Undefined data type
13. Can you compare undefined and non-defined variables?
Example answer: Both variable types here are linked to memory space. The undefined variable exists in memory space but without a value assigned to it.
The non-defined variable is non-existent in the memory space but is referenced elsewhere.
Example answer: We use timers to execute a specific function or task within a timeframe. They help us delay a program execution or code and help us execute the code on time. All timers operate in one thread, and subsequent events queue up afterward.
15. What is automatic type conversion?
16. What is event delegation?
This is called event delegation.
Example answer: When a user visits a website, the website will always store some tiny test files in the computer, which we call cookies. They automatically get created during user visits, but only when the user inserts some of their information into certain forms/subscriptions (e.g., shopping cart checkout or filling out forms).
The website always asks the user for permission to do this.
Another benefit of this technique is enabling a simple alias creation for a global variable (which is easy to reference). We see this mainly with jQuery plugins because jQuery allows the disabling of reference $ to the namespace of jQuery, for example, jQuery.noConflict().
19. Can you list the benefits of 'use strict' at the start of a source file?
- Prevention of accidental globals
- Removal of the 'this' coercion
- Easier debugging
- Strengthening the 'eval90' safety
- Preventing duplicate parameters (values)
Example answer: There are three types of errors: Syntax, Runtime, and Logical.
Syntax errors (or parsing errors) happen during code interpretation, but that code is invalid regarding syntax. These common errors occur when we type a semicolon but want to type a double colon.
Runtime errors (exception errors) occur after compiling and interpreting and during runtime. They occur if we call a function that doesn't exist or isn't declared at that time. The syntax is error-free when this happens.
Logical errors occur when we face code issues, but the syntax is valid. We can run the program smoothly, but we'll notice something wrong at the end. This is a complex error type, hard to identify or resolve, and unrelated to the runtime. These errors occur when data flow is faulty, or the developer makes some script logic mistake.
More hands-on experience in game development, mobile app, and desktop app development
Knowledge of the best IDE (integrated development environment)
Better expertise with network services, backend web apps, and microservices
A highly adaptable approach to their work
Excellent results on their technical tests
Diamant here adds:
It is better to come prepared with alternatives and solutions for potential challenges. Here are some hiccups that might happen:
No roadmap – Anything done without a plan or a systematic approach could fail later. Plan out every stage, anticipate every possible challenge, and store documents accordingly.
Budget issues – Allocate enough for everyone involved in the hiring process for recruiters, hiring managers, and potential new team members. Set aside an extra budget for possible obstacles that could hinder the hiring.
Candidate shortages – Remember that developer shortage is a common issue in the tech industry in recent years, further complicating how fast and efficiently you'll hire a great developer.
Time to hire – Remember that the process might take longer than expected (if you skip the services that hire developers for you).
The apps are scalable, quick, and highly performative, crucial for payment processing businesses or anything financial-related.
Marketing and advertising
Social media platforms
It shows high-speed performance
It enables interoperability
It improves cybersecurity
It enables easy testing and debugging
It's excellent for creating well-designed interfaces
It has a broad developer support community