Under the pressure

1. Coding of the day : None

2. JS of the day : Expressions / Operations and Numbers / Strings

Expressions and Operations :

• An expression is a valid unit of code that resolves to a value. There are two types of expressions: those that have side effects (such as assigning values) and those that purely evaluate.

• Nullish coalescing assignment (??=), also known as the logical nullish assignment operator, only evaluates the right operand and assigns to the left if the left operand is nullish (null or undefined).

• Destructuring, a JavaScript expression that makes it possible to extract data from arrays or objects using a syntax that mirrors the construction of array and object literals.

  • Without destructuring, it takes multiple statements to extract values from arrays and objects:

  const foo = ["one", "two", "three"];
  
  const one = foo[0];
  const two = foo[1];
  const three = foo[2];
  

  • With destructuring, you can extract multiple values into distinct variables using a single statement:

  const [one, two, three] = foo;
  

• Optional chaining, (?.) performs the chained operation on an object if it is defined and non-null, and otherwise short-circuits the operation and returns undefined. This allows you to operate on a value that may be null or undefined without causing a TypeError.

maybeObject?.property;
maybeObject?.[property];
maybeFunction?.();

Numbers and Strings :

• Number object, The built-in Number object has properties for numerical constants, such as maximum value, not-a-number, and infinity. You cannot change the values of these properties and you use them as follows:

const biggestNum = Number.MAX_VALUE;
const smallestNum = Number.MIN_VALUE;
const infiniteNum = Number.POSITIVE_INFINITY;
const negInfiniteNum = Number.NEGATIVE_INFINITY;
const notANum = Number.NaN;

• Template literals, ${expression} are string literals allowing embedded expressions. You can use multi-line strings and string interpolation features with them.

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