let x = 10;
let y = x++;
console.log(y);.webp){kind=logo}
Ask the right questions to secure the right ECMAScript talent among an increasingly shrinking pool of talent.
ECMAScript is a high-level, interpreted programming language that serves as the foundation for JavaScript, JScript and ActionScript. It was first standardized by Ecma International - a non-profit standards organization - in June 1997 to ensure interoperability of web-based applications across different browsers. The standardization process involved key industry players such as Netscape and Microsoft. ECMAScript has since evolved through several editions, with ES6 (ECMAScript 2015) introducing significant changes like classes and modules. Its dynamic typing, first-class functions and prototype-based object-orientation make it an essential tool for web development today.
The next 20 minutes of the interview should attempt to focus more specifically on the development questions used, and the level of depth and skill the engineer possesses.
An object in ECMAScript can be created using the object literal syntax, or the new keyword. For example: var obj = {}; or var obj = new Object();
'this' keyword refers to the object from where it was called. It provides a reference to the current object.
The == operator checks for equality of values but not type, while the === operator checks for both equality of values and type.
In ECMAScript, a variable can be declared using var, let, or const keywords. For example: var x; let y; const z = 10;
The different data types in ECMAScript are Undefined, Null, Boolean, String, Symbol, BigInt, Number, and Object.
Collaboration skills and experience with version control systems are important for working effectively in a team and managing codebase.
Understanding and applying best practices is key to writing clean, efficient, and maintainable code.
Experience with testing frameworks is important for ensuring code quality and reliability.
Keeping up-to-date with the latest features and updates is important for maximizing the potential of the language and staying relevant in the field.
Problem-solving skills are essential for any developer role, as they will often need to find solutions to complex coding issues.
A strong foundation in ECMAScript is crucial for developing efficient, reliable, and maintainable code.
The next 20 minutes of the interview should attempt to focus more specifically on the development questions used, and the level of depth and skill the engineer possesses.
Promises in ECMAScript are objects that represent the eventual completion or failure of an asynchronous operation, and its resulting value.
In ECMAScript, exceptions can be handled using try-catch-finally blocks. The try block contains the code that might throw an exception, the catch block handles the exception, and the finally block executes code after try and catch, regardless of the result.
'use strict' is a directive to enforce strict mode in ECMAScript. It helps catch common coding mistakes and unsafe actions.
In ECMAScript, undefined means a variable has been declared but has not yet been assigned a value. Null is an assignment value that means no value or no object.
Closures are functions that have access to the parent scope, even after the parent function has closed.
At this point, a skilled ECMAScript engineer should display strong technical expertise, problem-solving abilities, and understanding of modern ECMAScript standards and features. Red flags would include lack of hands-on experience, inability to articulate complex concepts clearly, or unfamiliarity with essential software development practices and principles.
let x = 10;
let y = x++;
console.log(y);let x = '5';
let y = +x;
console.log(typeof y);let arr = [1, 2, 3, 4, 5];
let sum = arr.reduce((a, b) => a + b, 0);
console.log(sum);let promise = new Promise((resolve, reject) => {
setTimeout(() => resolve('Done!'), 1000);
});
promise.then(alert);class Circle {
constructor(radius) {
this.radius = radius;
}
getArea() {
return Math.PI * this.radius * this.radius;
}
}
let circle = new Circle(5);
console.log(circle.getArea());let x = () => {};
console.log(typeof x);The final few interview questions for a ECMAScript candidate should typically focus on a combination of technical skills, personal goals, growth potential, team dynamics, and company culture.
Synchronous programming means that the code is executed sequentially from top-to-bottom, blocking execution until each operation completes. Asynchronous programming means that the engine runs in an event loop, allowing it to perform non-blocking operations such as network requests.
Generators are special functions in ECMAScript that can be exited and later re-entered, with their context (variable bindings) saved across re-entrances. They are defined using function* syntax.
In ECMAScript, inheritance can be implemented using the extends keyword in class declarations or class expressions to create a class as a child of another class.
Arrow functions are a shorthand syntax for writing function expressions in ECMAScript. They are anonymous and change the way 'this' binds in functions.
var is function scoped, while let and const are block scoped. const is a read-only reference to a value, meaning the value of const can't be changed.
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