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JavaScript isFinite() function

Description

The isFinite is used to determine whether a specified number is finite or not. isFinite is a top-level function and is not associated with any object.

Syntax

isFinite(number)

Parameters

number: The number to evaluate.

Note that the function returns false if the argument is NAN, positive infinity or negative infinity otherwise it returns true.

Example of isFinite() function

The following example shows how to use the isFinite() function.

JavaScript Code:

console.log(isFinite("Good Morning"));
console.log(isFinite("2009/01/01"));
console.log(isFinite(455));
console.log(isFinite(-9.34));
console.log(isFinite(15-12));
console.log(isFinite(0));

View the example in the browser

Live demo:

See the Pen isfinite-function-1 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

Returns all unique values of an array, based on a provided comparator function

Example:

const tips_uniqueElementsBy = (arr, fn) =>
  arr.reduce((acc, v) => {
    if (!acc.some(x => fn(v, x))) acc.push(v);
    return acc;
  }, []);

console.log(tips_uniqueElementsBy(
  [
    { id: 0, value: 'p' },
    { id: 1, value: 'q' },
    { id: 2, value: 'r' },
    { id: 1, value: 's' },
    { id: 0, value: 't' }
  ],
  (a, b) => a.id == b.id
)); 

Output:

[[object Object] {
  id: 0,
  value: "p"
}, [object Object] {
  id: 1,
  value: "q"
}, [object Object] {
  id: 2,
  value: "r"
}]