JS: isFinite

By Xah Lee. Date: .

isFinite is the value of the property key "isFinite" of the Global Object. 

console.log(globalThis["isFinite"] === isFinite);

Syntax

isFinite(arg)
  • First convert arg to a number.
  • Return true if arg is not any of NaN, Infinity, -Infinity, else false.

💡 TIP: better is JS: Number.isFinite, because it does not do auto conversion. 

console.log(isFinite("3"));
console.log(isFinite(3));

console.log(isFinite(NaN) === false);
console.log(isFinite("NaN") === false);
console.log(isFinite(Infinity) === false);
console.log(isFinite(-Infinity) === false);

JavaScript, Special Literals