Javascript Functions Development Tutorials, Guides & Insights

• Primitives hold a single value and are immutable.
• Non-primitives hold collections or behaviors and are mutable.

Example:

Conditional statements allow you to perform different actions based on different conditions.

let score = 85;

if (score >= 90) {
  console.log("A");
} else if (score >= 80) {
  console.log("B");
} else if (score >= 70) {
  console.log("C");
} else {
  console.log("D");
}

However, there are situations where you might want to control or change the value of this, and that's where call, apply, and bind come into play.

The call method allows you to invoke a function with a specified this value and arguments passed individually.

<table>
  <tr>
    <th>Function</th>
    <th>Description</th>
    <th>Example</th>
  </tr>
  <tr>
    <td><code>R.compose(...functions)
    Composes functions from right to left.
    R.compose(Math.abs, R.add(1))(-5) => 4
  
  
    R.curry(fn)
    Returns a curried version of the provided function.
    R.curry((a, b) => a + b)(1)(2) => 3
  
  
    R.filter(predicate, list)
    Returns a new list containing only the elements that satisfy the predicate.
    R.filter(x => x % 2 === 0, [1, 2, 3, 4]) => [2, 4]
  
  
    R.map(fn, list)
    Applies the function to each element of the list.
    R.map(x => x * 2, [1, 2, 3]) => [2, 4, 6]
  
  
    R.reduce(reducer, initialValue, list)
    Reduces the list to a single value using the reducer function.
    R.reduce(R.add, 0, [1, 2, 3]) => 6
  

Date-fns is a modern JavaScript date utility library that provides over 200 functions for manipulating dates without modifying native JavaScript objects.